Desktop and mobile devices support different texture compression formats. If you want your WebGL application to use compressed textures on both types of browsers, you must first choose a supported texture compression format.
You can set the default texture compression format for your WebGL application from one of the following locations:
The main difference between the Texture compression format setting in Build Settings vs the Player Settings is that the texture compression in Build settings is serialized in the Library folder; therefore, it’s not managed by version control.
Before you set the texture compression format, it’s important to determine which of these settings take precedence. The texture compression format value you set in Build Settings has priority over the value you set in Player Settings. By default, the Build settings value is set to Use Player Settings.
You can also customize the texture compression format for individual textures. The value you set for an individual texture overrides the default texture compression format value. For information on how to change the texture format of individual textures, see Texture Importer.