I wanted to replace an ingame-screenshot for the Amiga version of the game Links, because the quality looked JPEG-ishy with artifacts which looks very bad for everything with 256 colors or less. It was my own uploaded image so I wondered why I uploaded such a bad image myself. Well I made a new screenshot.
And after the upload it again looks bad. In no version in the image tool (normal, large, clicking on image itself) were I able to see the original quality non-artifact version of the image. Why is this the case? Normally I don't see such behaviour.
The original good quality image can be seen here:
https://nx13389.your-storageshare.de/s/C859TdaMg7Nxxtj
Compare it with the screenshots here or the game entry page itself:
https://www.uvlist.net/admin/listimages.php?game=17797
It also doesn't matter whether I upload the image as a 32, 24 or 8-bit image. It always gets the artifacts added.
Simply said I want to have it like the original png quality. At least as an option in the image edit tool so if I re-download images from image edit page I want to have a non-badly-artifact version to be available. Turned out that the old image that I replaced was very likely good quality as well, but got changed in a bad way that let me believe I made a mistake.
Image quality question
The basic concept is that images at 256 color or less are stored as 8bit PNG, while the ones with more colors are stored as jpeg.
The image you provided has 510 colors, that's weird as it doesn't look like that.
Maybe they used HAM or some copper effect.
Or the emulator was weird about rendering colors (I noticed something like that many years ago, where the rendered colors had actually more precision than the original hardware could, resulting is a lot of almost identical colors)
I just upped it using the 8bit option (that basically tries to convert it to 256 colors) and looks quite good, and comparing with the original image I can barely see any difference.
There could be other cases (i.e. AGA with copper backgrounds) that would require a real 24bit PNG ...
I could try to have this option available.
The image you provided has 510 colors, that's weird as it doesn't look like that.
Maybe they used HAM or some copper effect.
Or the emulator was weird about rendering colors (I noticed something like that many years ago, where the rendered colors had actually more precision than the original hardware could, resulting is a lot of almost identical colors)
I just upped it using the 8bit option (that basically tries to convert it to 256 colors) and looks quite good, and comparing with the original image I can barely see any difference.
There could be other cases (i.e. AGA with copper backgrounds) that would require a real 24bit PNG ...
I could try to have this option available.
I believe I know what happened. Its correct that the uploaded image from me had 510 colors. It was still the 24bit version. "Links" seems to use a strange graphics mode when it has so many colors on the Amiga OCS. But still I wondered why it would do this after I made a 8-bit version of the image with my image tool. It seems that by overwriting the 24-bit image to 8-bit colors and retaining the same file name on my HD it would result that the old file would still be in cache for file upload? It works now after I renamed my 8-bit version file name. The UVL option to upload as 8bit would also have worked. So if it was a caching problem and the UVL upload did not recogize the file change due to same file name it would make perfectly sense. I also wonder if it would be possible in the future to up the maximum color number to 512 or 4096 or something like that in the future? I have not much experience with more modern lets call them low-res "2D-graphics consoles" like the Neo Geo or NEC PC-FX and if those screenshot could turn out looking ugly. For 3D games or modern games with high resolutions that have high-res I understand the necessity to use compression.
Not sure about the name change issue, but yes, Neogeo (and post 1990 arcade games) SNES and similar usually have more than 256 colors.
I'll try to user PNG24 in case of >256 colors and low resolution (maybe up to 362 x 283 that is Amiga PAL low-res overscan, lets' say 400x300 to be safe)
I'll try to user PNG24 in case of >256 colors and low resolution (maybe up to 362 x 283 that is Amiga PAL low-res overscan, lets' say 400x300 to be safe)