If you do have very limited bandwidth, smaller files would help. It's easy enough to test. If you aren't able to resize your pictures, you could just try it with any small picture. Our profile pictures here are only around 5KB. You could right click to save it to your computer, and then try to re-upload it in a post. If that doesn't even work, then size is not the issue for sure. If it does work it might be the size or even something else about your pictures that is goofing it up.
Have you tried using a web browser other than Chrome to upload pics here? It might be a browser setting or add-on problem. Also, you could try running a speed test to see if your upload and download speeds are around what they should be for your level of internet service.
http://www.speedtest.net/
Sometimes I think the problem is just that your web traffic is getting stuck at a particularly slow node between you and the website's server. Kind of like the postal service when your package sits at one place for days on end, or takes the scenic route across the country just to go one state over!
