[coldtea]

>In fact, nearly every image viewing/accessing program assumes that your image content will just happily fit entirely in available RAM after decompression

Sounds like a totally reasonable assumption, for 99.9% of the cases (including graphic designers).

[BugsJustFindMe]

Absolutely, and the pervasiveness of that mindset leads to things like tearing through swap and grinding the computer to a halt because the user clicked on a random file. It doesn't take supergenious or paranormal powers to realize that files might be arbitrarily large. Engineers mostly just fail to care.