I usually save the pictures as-is. No file name changes.
The only exception are text-heavy images, such as screenshots of posts, infographics, infocharts, tutorials, etc. In that case, I will rename them with a brief summary, so I don't have to open every image to find what I'm looking for.
For example, this pic that I've uploaded with this posted is named "Swedish mustketeer.jpg" However, it will show up as random numbers because I use 4chanX like this guy
>>1220022.