The source of the IDE_WEBP.apl file is crucial. There are a few main ways to get it:
Convert WebP to PNG/JPG first using:
Enhancing ACDSee with WebP Support: A Complete Guide to Plugins and Compatibility acdsee webp plugin
Ensure the file is a standard WebP, as animated/transparent WebP files require newer software versions. The source of the IDE_WEBP
If you tell me which version of ACDSee you are currently using , I can help you confirm if it supports WebP natively or if you need a specific update. ACDSee Plugins acdsee webp plugin