That's because you're a Skilled user. Once you hit the Power User rank, then you'll be able to use 650 x 150 px size sigs. Until then, you're restricted to 650 x 100 px.
How big can I make my sig?
Ranking/badge system:
Reputation and Badges [8]
Actually, we're all using png - unless the sig is animated, in which case the format has to be gif ;-)
It's only the name which is gif (when you try to save it).
I guess you're confused because when you right-click on someone's sig and try to save it, the name is indicated as gif; if you look at the image properties (also via right-click on the sig), you'll see that's it's just a name issue. My browser is in German - "Adresse" means "address", "Typ" means "type", "Masse" = "dimensions" and "Grafik" = "image" ;-)
Hi Tim - it is 100 x 650 pxI checked some of my old pre-Power User sigs. You can also check your current sig size by clicking on your User CP, then going to "Edit Signature" and then checking what is indicated underneath the slot for "Option 2 - Upload Image From Your Computer".
Now i get it. I uploaded 650x150 siggy when Im supposed to have 650x100 only.. auto-resize :)
Am gonna make a new siggy using 650x100 :)
That is why I am not planning to upgrade to CS6 ... $199
