The Cartoon Express Master collection is a compressed zipped file, so you will need to unzip (extract, open) it first. On the PC you can use WinZip, and on the Mac Stuffit Expander. Once the file is uncompressed (opened) you will see all the images, as EPS files (editable vector) and PNGs (transparent background raster files).
The Cartoon Express' jpeg files are all 300 dpi, which are ideal for print. All of the files are in standard letter-sized (8.5" x 11") format. Many of the PNG files have continuous tone, with gradations and shading, and are ideal for the web and dropping on any colored background. The EPS files are resolution independant vector files, meaning they can be resized (blown up) to any dimension without loss of quality. So they can be used for larger print jobs and can also be ideal for print.
Right now, there are over 500 high quality illustrations, and the library is ever expanding. If you buy the entire collection for just $50, you are entitled to receive additional updated images. Although other clip art collections may have thousands and even millions of images, many of them are of mediocre quality--not to mention overpriced.