With 26 recipes, we have 100M of images.

A rough outline for a plan, based on what gnome-software does for screenshots:

1) Include the default image for each recipe and the chef images with the app, so we can populate the tiles without delay.

2) When opening the detail page for a recipe, start downloading any missing images.

3) We may or may not need to do the same trick gnome-software does, where it first downloads a thumbnail and then proceeds to load the full-size image.

4) Use ${sha256}-${original-name} to locate the images.

5) Store downloaded images in XDG_CACHE_DIR

Once we start getting new recipes and chefs by downloading data, the 'preinstall some images' part does not make too much sense anymore; we better just  make sure to download the default image for each new recipe quickly and make tiles deal with images that are still being downloaded.

There's an image-download branch that has an implementation.

*** Bug 780224 has been marked as a duplicate of this bug. ***

Image content will be hosted at static.gnome.org/recipes. Some example content is there already.

To do before this is ready for prime time:

- Verify that setting local images during recipe import and in other places works cleanly

- Store some negative cache entries so we don't try a failing url more than, say, once per day

- Consider a low-bandwidth setting that would try to load lower-resolution versions of the images, which will have to be provided on the site

- Handle change of image content, somehow (look what gnome-software does)

- Store version information in the recipe and chef databases:

[Metadata]
Version=1

- Make sure we load only images that are actually visible

- make sure libsoup builds and works on OS X