Here is an idea to make it easier for the player to download, install, and play. Prepackage the mod+game already modded and ready to play in a zip. This saves from having the player to mod it themselves, and run the risk of running into issues. Then include inside the zip links to the image packs to be used with the mod. This will allow the player to pick and choose which they wish to download. This will allow you to lower the initial file size. Mind you most players are not entirely scared of downloading 6 or 7 gigs for something they wish to play. This also depends on if the site the download is uploaded is clean and easy to use. Ex mega, google, etc. Just some suggestions to give you more options. Personally I would rather just download the whole thing in one go, and get to playing as quickly as possible. So looking forward to the end result.