[jacobolus]

By far most images in the wild are sRGB, and those that aren’t should typically be tagged with their color space.

Resizing in gamma-adjusted space (sometimes) causes nasty artifacts when resizing. If you can afford the CPU use, always convert to an approximately linear space first, then downsize, then convert back. If you get the gamma curve slightly wrong (e.g. gamma = 2.0 vs. 2.2) it’s not too big a deal, the resulting artifacts won’t really be noticeable, so feel free to use a square root routine or something if it has better performance.

[jacobolus]

But note if you go to a linear space, you need to bump up the precision of your numbers. 8 bits per channel doesn’t cut it anymore, you’ll want 12 or 16 bits per channel (or even better, a floating point number). This might have a big effect on performance.