I remember by galaxy nexus, which I used to play clash of clans with and left on overnight several times with the same stuff on the display. Didn't have any problem with it.
If you had it at a really high brightness and kept it on the same screen for really long, then you'd probably have a problem.
On an unrelated note, putting brightness above 80-90% tends to disproportionately take more battery life, where as for 0-80% it follows a linear function. Plus it seems to heat up the phone a bit more, I think.