the handling with background images change

[Kniebremser]

My theme has used different background images.
This I can not choose because they are located in the theme folder.
To use this, I have to upload it in the media folder.
Since then various image sizes are created. Needless!

Can not we make it easier!

In the Media folder, create a subfolder backgrounds.
That would be the default folder for backgrounds.
The images there are default not changed. (two files for each original image and thumbnail for the costumizer)
Own background, you could upload via ftp.
In the media uploader to add a new function -> upload to background images.
These are the media center not visible in the normal Pictures.
In the costumizer you would have a choice of the deposited background images for preview.

This would make it easier for Theme developers additional background images through a plugin or. zip to make available.

[ericlewis]

There's a few things you bring up here.

Creating multiple sizes of every attachment is the current functioning paradigm we have in WordPress media management. There's some alternative ideas to how we should handle things, such as serving new image sizes on the fly. Our current paradigm works well enough, but if you have bright ideas, please lay them out on that ticket.

The manner in which themes utilize (or don't utilize) the WP media library for managing background images is completely up to the theme developers. The bundled themes (e.g. ​Twenty Fourteen) offer great UI and community-backed practices for using the media APIs, serving as a model for anyone doing WordPress development to take a look at for inspiration.

Closing this out as invalid, since there aren't good points to continue a conversation here. I understand your desire to make these things easier to work with. Feel free to reopen with more developed points.