That’s a totally reasonable question. 245px is the max that will display for two to a row. If you make them wider than that, they’ll still be shrunk to 245px, and depending on the height they may display as still images until the user clicks. You will always have that 10px gap in the middle. Here’s a handy guide for what heights you can play around with (though the size limit is actually 2MB for 245px gifs).
And thanks! I don’t really do much beyond gif’ing random scenes, but thanks.