So for about 2 weeks now the Samsung Message app changes my chat backgrounds to default white. No matter how many times I change it to what I like, it keeps restoring to default.
Update the Samsung Message app and install the latest Android OS on your phone.
Thanks to everyone who helped but I just back up some of my files(music, pics) and uninstalled some old games and seems th problem was with memory. Bc now it's all right.
Btw I did all of the above solutions before commenting here just forgot to mention.