In your site directory check the permission of “Uploads” folder. Change it to 755.
I assume that the problem has been fixed because the sidebar is showing, at least here.
Regards
Try using http://pixlr.com/editor or any other photo editor to re size the image to your desired size.
1) Upload your image
2) Go to Image> Re-size
3) Enter your desired dimensions.
4) Save.
I hope it helps.
