When using the mte-imaging module, the system-wide component for ImagingSupport is still the DefaultImagingSupport, which is injected in different other classes. Especially the info.magnolia.imaging.functions.ImagingTemplatingFunctions use the ImagingSupport, resulting in the following behavior:

Even when a theme + imaging support and variations are configured will the DefaultImagingSupport be used always returning the original image instead of variations of it (when calling info.magnolia.imaging.functions.ImagingTemplatingFunctions#getImageVariationLinkFromBinary(javax.jcr.Node, java.lang.String)).

Solution

Provide a ThemeDelegatingImagingSupport that delegates to the theme's imaging support and falls back to the DefaultImagingSupport when no theme can be found.