Photo V2.0.3
This might be a take-over from V1
create new document 512x512px, use default 72 dpi
Add rectangular shape of 1x1px
rasterise layer
use move tool / transform panel to resize pixel layer 100x100px (reduces DPI to 1/100th - unfortunately resulting DPI is not visible for pixel layers, only image layers show this)
rotate pixel layer by 45 degree
use channels panel, to fill pixel alpha
Result: you get a layer of size more than 51.200x51.200 px, and it is very tedious to get rid of those unwanted extra pixels outside the visible canvas. For unknown reasons, if you reduce layer DPI, the layer keeps some hidden / secret information about its old number of pixels, and there is no way to get rid of them after transforming. You would need to rasterise & trim before transforming. Those fully transparent superfluous extra pixels outside the visible canvas should not be filled at all.