How are you setting the images for the different UIControlStates on the button? Are you setting a background image for UIControlStateHighlighted as well as UIControlStateSelected?
UIImage *someImage = [UIImage imageNamed:@"SomeResource.png"]; [button setBackgroundImage:someImage forState:UIControlStateHighlighted]; [button setBackgroundImage:someImage forState:UIControlStateSelected];
If you're setting the selected state on the button touch down event rather than touch up inside, your button will actually be in a highlighted+selected state, so you'll want to set that too.
[button setBackgroundImage:someImage forState:(UIControlStateHighlighted|UIControlStateSelected];
Edit:
To sum up my remarks in the comments and to address the code you posted...you need to set your background images for the full UIControl state that you're in. According to your code snippet, this control state would be disabled+selected+highlighted for the duration of the network operation. This means that you would need to do this:
[button setBackgroundImage:someImage forState:(UIControlStateDisabled|UIControlStateHighlighted|UIControlStateSelected];
If you remove the highlighted = YES, then you would need this:
[button setBackgroundImage:someImage forState:(UIControlStateDisabled|UIControlStateSelected];