Scaling Issue

I have really been struggling with the scaling of my app in Axure, I have been creating all of my work in Photoshop 2019 which actually provides a blank document preset in the size for an IPhone. With this I chose the IPhone 8+ size as I know that this phone in particular is the one of the fairly new phones out and it very much markets at the same audience as the one for the GRLZ app.

When exporting my content out of Photoshop, I first flatten the image to ensure everything stays in place and then save the file as a JPEG. I then drag the file into Axure and rescale it to 552 x 1048 however, this hasn’t been working out well when previewing my app as it they all appear as different sizes and make the overall feel of the app look messy.

I am going to watch some tutorials online to see if this is a common problem that I am experiencing.