Fun image processing / compression trivia: I’m pretty confident this is the least compressible fanart I have ever come across let alone submitted.

The original is 23.18 MiB (losslessly compressed) with a res of 2800x4218. Normally given those dimensions and the subject matter, I’d ~halve those dimensions, recompress the image using WebP quality 80~85, and the resulting file size for fanart at similar settings averages out to ~200 KiB (give or take - approaching 300 KiB for larger or visually complex images like this one, but lower for smaller or visually simple images). This is more respectful of server storage/bandwidth costs and the load times for anyone who gets served the same image I submit and not one that’s further recompressed by their instance (the latter being what lemmy normally does, the former being what Mbin normally does). Even for complex images I usually don’t struggle to hit a max size of ~300KiB, and when I do it’s usually because of film grain / digital noise which can be reduced prior to compression to improve the file size vs perceived image quality tradeoff, or at most it’s high-complexity detail which gets simplified down to something more manageable with a more aggressively lowered resolution (like targeting a step down from ~full HD instead of ~full HD resolution).

In this case going down to 50% dimensions at my preferred quality target of 85 with WebP compression still results in a file size of ~900 KiB! Even when going down to 40% dimensions and only going for quality 80 (the lower limit of my preference instead of my preferred target of 85) I’m at ~490 KiB, and still ~440 KiB at 33% dimensions at quality 80, still bigger than anything other fanart I’ve encountered because it has so many fine details that aren’t film grain / digital noise and so can’t be reduced with some light denoising. Trying to balance my preference between image quality and server resources / end user bandwidth and load times, I ended up dropping down to 40% dimensions at quality 72 to get ~300 KiB (broadly speaking in the context of digital fanart, for maximizing image quality vs file size, extra resolution with more aggressive compression beats lower resolution with less aggressive compression).

Can anyone tell the difference in quality while casually browsing? Well, probably not 😅, which is why stuff like lemmy will recompress it even more than what I’ve done here - but professionals have standards damn it.

Tune in next episode for more uselessly specific fanart image compression trivia.

Edit: since I last investigated this, it looks like lemmy’s behaviour regarding recompression of images has changed; on lemmy.world, sh.itjust.works, and aussie.zone I’m now seeing the original image submission without the extra layer of recompression, making it actually slightly more relevant what I choose to do lol