Please refer to this documentation link for comprehensive details on the Custom Preset and its configuration settings. Additionally, there's an earlier thread that addresses a similar question which might be helpful. Custom | Adobe Experience Manager Re: Custom default output presets - pptx and docx...

@sschnelbach , can you please elaborate on how you referenced the image from outside. Was it: 1) Uploaded on to assets 2) xref from another site 3) any other way Thanks,