Change of image due to template restrictions - Help wanted!

There has been a change of image in the blogosphere for me as the previous template I had selected did not fit my cartoon in (see link in post above). I pasted the image in and it didn't fit the template, thus the change of template. I saved the cartoon as an image and inserted it into the post but the saved image didn't appear large enough to read clearly. I gave up and used the hyperlink. Right now I am more interested to know how I might have changed the template or designed my own to fit the cartoon in. Any help would be appreciated. Ta very much

BAM