Error: The file name must end with .xml or .png

Android accepts only .png, .jpg, .gif and .xml files as drawable resources. If you have file .db file then put that file in assets folder.

I had a similar problem after I converted .png icons to .webp format. The file was created in the xxhdpi folder and not used. I didn't remember creating or using photothumbs.db in any of my app's xml and java files. The error was cleared after simply deleting the photothumbs.db file. Create a backup copy of the file anyway for safety before deleting it.