The most daunting task is finding images that fit, this will simplify that task - placehold.co.za.
Placehold.co.za is a image placeholder creator for designers/developers to showcase design layouts utilizing correctly sized content.
You can generate any size images you require by simply setting an img tags src to http://placehold.co.za passing 1 simple parameter, widthxheight
A sample image as seen to the left can be generated with <img src="http://placehold.co.za/150x400" />.
The images constrain proportions and keeps the font size relational to the size of the image.