10017: Layer uses symbol level drawing with a picture marker symbol
Your map layer uses picture markers in symbol level drawing. Picture markers can contain transparent colors, which can impact drawing performance in basemap layers or optimized map services.
Symbol level drawing allows you to choose the drawing order of individual layers of a given symbol or set of symbols to achieve specific cartographic effects. In general, using transparency would defeat the purpose of using symbol level drawing. If your application warrants the use of transparency in conjunction with symbol level drawing, you can choose to mark this warning as an exception to avoid receiving the warning next time you analyze the map. Basemap layers and optimized map services will use a slower method to perform symbol level drawing in this case.