Let's see:

• The maximal vertical dimension of a signature image can be 200 pixels PASS
• The maximal horizontal dimension of a signature image can be 700 pixels PASS
• The maximal combined image size of signature images can be 80 kilobytes FAIL
• Signature images may not contain filtered expressions FAIL

As you see, that image is not allowed. Please, next time you want to add another image to your signature, go through the list yourself, so you won't have to ask here.

While we're at it, the images in your signature combined are 99 kilobytes big. Please remove one of them.