19-05-2021, 08:43 PM
I fear we're going around in circles. I'll give it one more go - but I'm anxious not to offend or fall out with anyone. In fact, that's the very reason I'm trying one more time. It would be far easier to simply tell you you're wrong and be done with it. But I don't think you're wrong. I do, however, think that we're talking about different things for some reason. And because we're talking about two different things, it is entirely possible that we're both right! And we are, whether you see it or not 
You are talking about the entire process of taking a raw image and preparing it for the web.
This will, of course, involve many processes that include cropping and resizing (changing the pixel size). So once all those are done, you will then save it as a JPEG. As I say, no argument from me - it's exactly what I and many others will likely do, and as I showed you earlier, I had that advice on my website since 2004 (for about a decade IIRC).
I hope we can agree on that. I've repeatedly said that I don't dispute it, both here and in previous posts.
-----
Let's turn to my statement: "As I say, I'm not aware of any reason why the order matters between resize and crop - it's a matter of "operator preference"."
The key thing here is this: these 2 steps are just a part of the entire process outlined above. Only 2 steps out of what might be many if you have to do colour correction, image rotation, image stitching, sharpening, noise reduction, manual editing, etc, etc.
As I say, you broadened out the discussion to include the entire process, but again, I'm just talking about 2 of those steps.
Above you said "broader point (file size)". But the broader point is not file size - the broader point is the whole process of preparing an image for the web, as explained above. Perhaps now we've found the point that you've misunderstood? I feel optimistic that this might be the case, as if so, that moves us forwards - and I can apologise for not being clearer earlier.
When you are preparing an image for the web, you will - as I say above - crop and resize during the "session". Most likely I'll crop, then resize, as I normally want my images to be a specific width* to fit the width of the main content column on my website. But in terms of final image quality, it doesn't matter which way around you perform those sub-steps. The image-resizing algorithm specifically (what happens when you do Image -> Resize (of Shift+S) in Paint Shop Pro**) does not care if it's working with the original massive "raw" image (as opened straight from the file the camera or scanner made) or a cropped, more manageable version of the same.
* That's an example of "operator preference. As the operator of PSP, I might want the image to be a certain width, so that's why I'd crop then resize. It has no effect on the overall image quality, but it does ensure that it ends up being exactly the width I want. But there might be other scenarios where the aspect ratio matters more than the actual dimensions - in that case I might be tempted to resize (to make the image more manageable in PSP, and also closer to the approximate final size I'm after), then I'll do the crop, keeping an eye on the aspect ratio numbers in the status bar as I make the selection, and appreciating that I can have the whole pre-cropped image on the screen at 1:1 zoom level so my crop can be pixel-perfect. These are just examples - every operator will have their preferred workflows.
** PSP V6 and V7 - I haven't seen V8 in over a decade, so can't remember if it's the same.
So the end result is the same, whether you make the crop, then resize - or resize, then crop. When you File -> Save As, that's when the JPEG encoding algorithm runs to take the image held in RAM (in totally uncompressed form) and turns it into the JPEG which obviously will have a much smaller file size. So whether you crop before resize - or the other way around - is completely up to the user, and doesn't affect the end picture quality.
Yes, you're making the point that if you don't crop, then the area of interest is smaller (and of less quality) than it would otherwise be. Yes - that's utterly obvious, and I have never disputed that (nor did I need it pointed out). But if you are planning to crop and resize an image before making it into a new JPEG file, it really doesn't matter whether you crop before or after you resize - they will look pretty much identical and have almost identical file sizes. That is simply a fact. Honestly, I'm not sure how else I can explain it.
Again, if a given image is going to be cropped and resized before posting to the web, it doesn't matter which way round you do it in terms of image quality. And cropping and resizing are just 2 out of the potentially many steps you might perform before saving the final JPEG.
When it comes to preparing images for the web, we both have long-standing websites (21 years in my case), and we both have high quality images on them. Therefore, neither of us lacks understanding or experience when it comes to preparing images for web use. At a stretch, it's perhaps just about possible I have have slightly more understanding of the inner workings of a a graphics program - that'll be because of my knowledge of television, though I do my very best to stay away from video as I'm an audio person. But having said that, I really don't want to claim any knowledge of these inner workings - but I have many colleagues who could help me if I ever needed to know. Likewise, we all know (and I have already acknowledged) that Jeffrey will have this sort of in-depth knowledge too, as he knows far more about video than I. Indeed, as I explained in my last post, I thought that's where he was coming from - thinking that the image resizing algorithm might perform better with the smaller cropped image - and back in the 1990s, that might well have been the case, but when I said "I'm not aware of any reason why the order matters between resize and crop", I was making the point that problems with image resizing algorithms were historic problems that had gone away by the time of PSP6. But as he changed to "crop before compress" in post #17, it's clear that "crop before resize" in post #15 was just sloppy language or a brain fart. No problem - we'd moved on from that before you joined the thread and told me I was making a wrong statement.
So this is not a technical argument as such - as I say, I believe we're both right. Instead, it's a communication problem. I could accept that I'm not being clear enough. But I'm also aware that I'm writing long posts, and I do wonder if they are being read properly? My fault for not being more concise, perhaps? Well yes, but I hate that social media has reduced internet communication to short sentences at best, and find it frustrating that forums appear to be going the same way. Perhaps I'm a bit nostalgic for the 1990s, when text was almost all we had... But perhaps I should just restrict my lengthy ramblings to my website, and give up trying to post on forums? After all, I've almost entirely given up posting on social media... But if I don't feel free to contribute to this forum without causing confusion by writing in my preferred style, why on earth am I still paying the bills?
I'll repeat what I said at the start. This is an attempt to help. I hope I haven't offended or upset anyone. And if this post hasn't helped, tell me what I need to do...
I hope this is received in the constructive and conciliatory spirit in which it is offered - life is too short for fighting and point scoring on an internet forum. We're both right, for goodness' sake!
Mark
You are talking about the entire process of taking a raw image and preparing it for the web.
This will, of course, involve many processes that include cropping and resizing (changing the pixel size). So once all those are done, you will then save it as a JPEG. As I say, no argument from me - it's exactly what I and many others will likely do, and as I showed you earlier, I had that advice on my website since 2004 (for about a decade IIRC).
I hope we can agree on that. I've repeatedly said that I don't dispute it, both here and in previous posts.
-----
Let's turn to my statement: "As I say, I'm not aware of any reason why the order matters between resize and crop - it's a matter of "operator preference"."
The key thing here is this: these 2 steps are just a part of the entire process outlined above. Only 2 steps out of what might be many if you have to do colour correction, image rotation, image stitching, sharpening, noise reduction, manual editing, etc, etc.
As I say, you broadened out the discussion to include the entire process, but again, I'm just talking about 2 of those steps.
Above you said "broader point (file size)". But the broader point is not file size - the broader point is the whole process of preparing an image for the web, as explained above. Perhaps now we've found the point that you've misunderstood? I feel optimistic that this might be the case, as if so, that moves us forwards - and I can apologise for not being clearer earlier.
When you are preparing an image for the web, you will - as I say above - crop and resize during the "session". Most likely I'll crop, then resize, as I normally want my images to be a specific width* to fit the width of the main content column on my website. But in terms of final image quality, it doesn't matter which way around you perform those sub-steps. The image-resizing algorithm specifically (what happens when you do Image -> Resize (of Shift+S) in Paint Shop Pro**) does not care if it's working with the original massive "raw" image (as opened straight from the file the camera or scanner made) or a cropped, more manageable version of the same.
* That's an example of "operator preference. As the operator of PSP, I might want the image to be a certain width, so that's why I'd crop then resize. It has no effect on the overall image quality, but it does ensure that it ends up being exactly the width I want. But there might be other scenarios where the aspect ratio matters more than the actual dimensions - in that case I might be tempted to resize (to make the image more manageable in PSP, and also closer to the approximate final size I'm after), then I'll do the crop, keeping an eye on the aspect ratio numbers in the status bar as I make the selection, and appreciating that I can have the whole pre-cropped image on the screen at 1:1 zoom level so my crop can be pixel-perfect. These are just examples - every operator will have their preferred workflows.
** PSP V6 and V7 - I haven't seen V8 in over a decade, so can't remember if it's the same.
So the end result is the same, whether you make the crop, then resize - or resize, then crop. When you File -> Save As, that's when the JPEG encoding algorithm runs to take the image held in RAM (in totally uncompressed form) and turns it into the JPEG which obviously will have a much smaller file size. So whether you crop before resize - or the other way around - is completely up to the user, and doesn't affect the end picture quality.
Yes, you're making the point that if you don't crop, then the area of interest is smaller (and of less quality) than it would otherwise be. Yes - that's utterly obvious, and I have never disputed that (nor did I need it pointed out). But if you are planning to crop and resize an image before making it into a new JPEG file, it really doesn't matter whether you crop before or after you resize - they will look pretty much identical and have almost identical file sizes. That is simply a fact. Honestly, I'm not sure how else I can explain it.
Again, if a given image is going to be cropped and resized before posting to the web, it doesn't matter which way round you do it in terms of image quality. And cropping and resizing are just 2 out of the potentially many steps you might perform before saving the final JPEG.
When it comes to preparing images for the web, we both have long-standing websites (21 years in my case), and we both have high quality images on them. Therefore, neither of us lacks understanding or experience when it comes to preparing images for web use. At a stretch, it's perhaps just about possible I have have slightly more understanding of the inner workings of a a graphics program - that'll be because of my knowledge of television, though I do my very best to stay away from video as I'm an audio person. But having said that, I really don't want to claim any knowledge of these inner workings - but I have many colleagues who could help me if I ever needed to know. Likewise, we all know (and I have already acknowledged) that Jeffrey will have this sort of in-depth knowledge too, as he knows far more about video than I. Indeed, as I explained in my last post, I thought that's where he was coming from - thinking that the image resizing algorithm might perform better with the smaller cropped image - and back in the 1990s, that might well have been the case, but when I said "I'm not aware of any reason why the order matters between resize and crop", I was making the point that problems with image resizing algorithms were historic problems that had gone away by the time of PSP6. But as he changed to "crop before compress" in post #17, it's clear that "crop before resize" in post #15 was just sloppy language or a brain fart. No problem - we'd moved on from that before you joined the thread and told me I was making a wrong statement.
So this is not a technical argument as such - as I say, I believe we're both right. Instead, it's a communication problem. I could accept that I'm not being clear enough. But I'm also aware that I'm writing long posts, and I do wonder if they are being read properly? My fault for not being more concise, perhaps? Well yes, but I hate that social media has reduced internet communication to short sentences at best, and find it frustrating that forums appear to be going the same way. Perhaps I'm a bit nostalgic for the 1990s, when text was almost all we had... But perhaps I should just restrict my lengthy ramblings to my website, and give up trying to post on forums? After all, I've almost entirely given up posting on social media... But if I don't feel free to contribute to this forum without causing confusion by writing in my preferred style, why on earth am I still paying the bills?
I'll repeat what I said at the start. This is an attempt to help. I hope I haven't offended or upset anyone. And if this post hasn't helped, tell me what I need to do...
I hope this is received in the constructive and conciliatory spirit in which it is offered - life is too short for fighting and point scoring on an internet forum. We're both right, for goodness' sake!
Mark
