On traditional sites, Wagtail has a template tag that makes it easy for a frontend developer to request an image of a particular size. Currently, the Wagtail API provides two solutions:
- Add an ImageRenditionField to the model, that allows an image in a particular placement on a page to be requested at a pre-defined size. This is the approach we recommend in most cases.
- Use the dynamic image serve view, which allows any image to be rendered at any size. Note that this approach may require extra work, since a key is required and you'll need a secure way to pass the key back and forth. Without this, there's a higher risk of crashing your site, by an attacker requesting the same image in millions of subtly different ways.
Neither of these solutions are easy for a frontend developer. They may not have the access or skills to add an ImageRenditionField, and crafting a URL to the dynamic image serve view is tricky because it needs to be signed and there currently isn’t a library or code snippet to do this from JavaScript. Hashes also need to be generated and the current JS version is complex.