@Anonymous
Yes, but what I am saying is that the orientation of the image is based on the human viewer. If I take a picture with the camera upside down, the image will be the correct orientation for the camera, but the image will be upside down for the viewer. So, how would the technology know? And actually there are some technologies that can automatically analyze the image and determine the correct orientation - but that is not PowerApps.
As for your rotation, no, there is nothing that can be done in PowerApps to correct an image at 45 degrees. You can adjust for 90, 180, and 270.
What we do with this is as I mentioned (but it always take a human to first correct it). We typically do this when storing an image attachment from an Email message. The user views the images in the App and if they are rotated wrong, they click on the correct rotation. We then store that rotation information in the record with the image. So, if we recall it again, we can apply the chosen rotation.
Now, if all of your images are rotated 90 degrees, then you can apply a universal rotation for all of them. But I sense you have some that are and some that aren't.