I was working on some custom magazines and noticed that there weren't any mod resource files to make this an easy job.  So, I cleaned up a handful of magazines from the vanilla game in Gimp and upscaled them to 2048x2048.  Use these however you feel fit.  Since these were made using Gimp, all files are in XCF format.  You will need a DDS plugin to export your final product.

For users without GIMP, there is an option to download the files exported to PNG with maintained alphas to import into your editor of choice.