You may want to check on the size of the file that the picture is too. That was my problem when I first started posting pictures. If it takes a really long time and doesn't post, I bet it is the size of the file.
I use the PAINT program on the computer pull up the picture, there is a button towards the left that says RESIZE. I usually take it from 100% to 20-25%. And then save it again. Try it an see if you can bring up the picture then.
Hope this helps.