I downloaded an app from Cydia called "Conway's Game of Life" to both my iPhone and my computer. On the iPhone it renders correctly, but on the computer some of the PNG files of the Cydia .deb archive are corrupt. Their thumbnails are totally black and when opened with a simple program like Windows Photo Viewer they appear blank, but in the correct height and width measures. I looked into that and these signs indicate that they are corrupted (also GIMP couldn't open it saying it's corrupted). The same thing happened when I tried downloading different apps.
I don't actually run the .deb files on my computer, but I unzip them and check their contents (I tried with two programs, 7-Zip and AnytoISO, and they both produced the same corruption results, so problem doesn't lie in the unzipping programs).
Any ideas why and how I can solve this? I need them to display correctly on the computer.