I forgot to mention that there are other setup incompatibilities 
which might be the problem. Maybe browser version, or 
OS type or version, etc. This doesn't really explain my own 
problem -_-' since my setup is relatively new... 

As a last resort, there are free image hosting options so 
people like me don't have to worry about bandwidth. These 
free hosts are common on EBay, for instance - I happen to 
use Photopoint, and there are a couple other services. 

NOTE THAT IN THE CASE OF PHOTOPOINT (and I'm assuming other 
services), YOUR SETUP MUST STILL BE ABLE TO MOVE FILES FROM 
HARD DRIVE THROUGH BROWSER TO SERVER. Since I noticed that 
I can upload images to Photopoint, but not Animanga, I'm 
assuming it's a server incompatibility or something. ...

[test: photopoint and Animanga upload]