Images: captions and footer

1. In my footer, I have the widget for blogs, is there a way to change it from a square to a rectangle image? Right now it is cropping out the right and left side of the blog image so it doesn’t look right.

2. Is there a way to change the font for the caption of an image? I’d like to make the font bigger, left-justified, and italicized if that’s possible.

Thank you