Thumbs.db warning while playing jpeg sequence

Hi there,
I’ve made a material that use a mediaplayer texture, which one plays a png sequence (looping).
The sequence has a specific name (heart_[###].png), but while playing, UE spams a warning :

LogImgMedia: Warning: FGenericImgMediaReader: Unsupported file format in ../../../../../../UnrealEngineProjects/MyGame/Content/Movies/heart/Thumbs.db
LogImgMedia: Warning: FGenericImgMediaReader: Failed to load image ../../../../../../UnrealEngineProjects/MyGame/Content/Movies/heart/Thumbs.db

Of course that file doesn’t have the same extension than the png ones, and it appears that file doesn’t even exist in the folder. Any advice there ?