The DooM High Resolution Texture Pack for GZDoom is 90.4MB in size. The file name is jdtp-20081108.pk3. It was released on November 8, 2008. This is a work in progress so I linked to the download page that lists the various versions of this pack that are available. To install the Texture Pack automatically every time you use the gzdoom.exe add this to the zdoom-(user) file (if you use C:/DOOM2 as your directory):
Note: The zdoom-(user) file is created the first time you load GZDoom. So you need to place the Doom2.wad file, the GZDoom files and the jdtp-20081108.pk3 file in the same directory then run the gzdoom.exe. When you exit the game the zdoom-(user) file will have been created. Also the (user) in the zdoom-(user) file is your user name. If your user name is Bob it will look like this: zdoom-Bob.
This version of the Texture Pack works with the DelphiDoom, Doomsday, GZDoom and Skulltag ports. There are also versions of this Texture Pack available for the Edge, Risen3D and Vavoom ports too. Instructions for loading the Texture Packs is provided on the download page.