signal strength shouldn't be a problem. Even if your network is at a crawl, you'll just download the pic at an extremely slow rate.
can you change the file type? For instance, if you typically save as a .JPEG, can you save as a .TIF or .BMP?
try following these instructions from Microsoft, it may fix your problem.
http://support.microsoft.com/default.aspx?scid=kb;en-us;810978