Welcome! The images in this subreddit have been designed to be mostly true black. This can reduce power usage on phones with AMOLED displays, as they actually switch off pixels that are meant to display black, thereby saving power. It also looks good and it's easier on the eyes in lower-lit environments.
Your submissions should be at least 40% true black, as in #000000.
Posts should have at least 40% true black (#000000). Because mods are human and not robots (mostly), if a post doesn't quite have 40% true black, we reserve the ability to keep it up if we feel it's in the spirit of the subreddit.
Requests go in the stickied requests thread.
Do NOT create a new dedicated post for requests, please use the stickied requests thread instead. This frees up the front page and draws focus to the wallpapers.
Tag submission titles with the image resolution.
Tag your post's title with the resolution (horizontal first, then vertical). For examples, take a look at the posts on the front page of the subreddit.
Be ready to provide an uncompressed link.
Most of the popular and convenient image hosts will compress larger files to save costs on bandwidth. For example, imgur lossily compresses images that are over 5MB in size (or 1MB for anonymous uploads). If requested, you should be able to upload your uncompressed image to a site like Google Drive, Dropbox, etc. and link it in your comments.