Issues with images & gallery

I'm having a number of issues with adding media to pages, both individual images and galleries. For starters, please see my issue with individual images (http://jpgrennier.com/artwork/). As you can see the grey line (and edit link if I'm logged in) is not where it's supposed to be. Next, another issue when I attempt to use the gallery (http://jpgrennier.com/writing/). The link extends far beyond the image. Also with the gallery, wondering if I could use medium sized images versus thumbnails and remove the white border. Thanks. jpg