Hi,
I am going to ask first here and then file a bug if it's indeed one. But when using sitkcers in iMessage apps, there appears to be 2 different sizes. When you use the sticker as a standalone imaage (just send it like a normal image) and when you stick it into a message bubble. The latter results in a much larger version of the sticker and it's even worst when you rotate the device, the image turns gigantic.
You can see the behavior in the default stickers provided by apple as well. But how do they keep the resolution so nicely? This gets even worst with larger screens.
https://s32.postimg.org/b0zfbp1c5/Simulator_Screen_Shot_23_Jun_2016_14_13_53.png
and when rotated
https://s31.postimg.org/67mey3osr/Simulator_Screen_Shot_23_Jun_2016_14_14_00.png
Thanks!