17-05-2021, 01:05 PM
Crop before compress - yes. But you said crop before resize. Resize, as in change the number of pixels. If by "resize" you meant JPEG encode, that wasn't clear from what you wrote. Call me pedantic, but this is analogous with what is an everyday battle for me as an audio person, where I try my best to persuade people to say "data rate reduction" or "dynamic range processing" instead of "compression"...
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". Obviously the JPEG conversion comes as the very last step when you save the file, but it won't care what order you made the various steps before clicking Save.
GIF is only 256 colours, of course. Not exactly lossless if the source is a full colour photograph, but occasionally it can look pretty good. Attached is the first "real" picture I ever saw on a computer - this was on a Unix terminal at university in 1991, and was absolutely amazing at the time. I remember the monitor seeming huge too - CRT, of course, and Trinitron, IIRC. It was probably "only" 19", but every other monitor on campus was a 14" VGA running DOS applications in 80 column text mode 99% of the time (Windows wasn't used much back then). I don't know what resolution the Unix terminal was running at, but it was pretty high for the time - you could comfortably get several 80 column text windows on the screen, and my young eyes couldn't see the pixels or phosphor stripes. The image is 1024 by 768, and it was nowhere near filling the screen. Of course, the very high physical resolution of the display would have made up for the lack of available colours. Looking today on a screen with fewer DPI the artefacts are clearer, but weaker glasses cures that!
I'm fairly sure the only reason GIF remains popular today is for animations. There is an animated variant of PNG (APNG), but GIF seems to be the most commonly used still.
The main drawback with a lightly data-rate reduced JPEG is that it's only 8 bits. If your camera can make RAW files, it'll typically match the bit-depth of the sensor, giving you a lot more freedom at the post-processing stage. Had a lot of fun with that a while back - don't get so much time for photography these days...
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". Obviously the JPEG conversion comes as the very last step when you save the file, but it won't care what order you made the various steps before clicking Save.
GIF is only 256 colours, of course. Not exactly lossless if the source is a full colour photograph, but occasionally it can look pretty good. Attached is the first "real" picture I ever saw on a computer - this was on a Unix terminal at university in 1991, and was absolutely amazing at the time. I remember the monitor seeming huge too - CRT, of course, and Trinitron, IIRC. It was probably "only" 19", but every other monitor on campus was a 14" VGA running DOS applications in 80 column text mode 99% of the time (Windows wasn't used much back then). I don't know what resolution the Unix terminal was running at, but it was pretty high for the time - you could comfortably get several 80 column text windows on the screen, and my young eyes couldn't see the pixels or phosphor stripes. The image is 1024 by 768, and it was nowhere near filling the screen. Of course, the very high physical resolution of the display would have made up for the lack of available colours. Looking today on a screen with fewer DPI the artefacts are clearer, but weaker glasses cures that!
I'm fairly sure the only reason GIF remains popular today is for animations. There is an animated variant of PNG (APNG), but GIF seems to be the most commonly used still.
The main drawback with a lightly data-rate reduced JPEG is that it's only 8 bits. If your camera can make RAW files, it'll typically match the bit-depth of the sensor, giving you a lot more freedom at the post-processing stage. Had a lot of fun with that a while back - don't get so much time for photography these days...
