So ... does everything except .png end up with the blue square and enlarge picture?

the blue square happens when the image dimensions are too large for the forums. it has nothing to do with the file type.

Immo, youre alive........

Watjalukinat

Immo is correct.  The lines come up when he image is larger then the thumb nail pic.  If you are wanting to have a sig for yourself, we have a standard size of 400x120 for our sigs.  

If you keep at that resolution, then you should have any issues.

yeah, adjusted it.