08-26-2017, 08:21 AM
I hope I am understanding your requirements correctly.
Create a new image 512x512.
Use (File > Open As Layers) to open your 4 256 x 256 images. Each image will be on its own layer.
(If it is only 1 image that you are displaying 4 times: use Open As Layers to open the 1 image. Then, in the Layers Dialogue, use the Duplicate button to duplicate the image 3 more times.)
Use (Image > Guides) to create 1 vertical and 1 horizontal guide at the 256 pixel position. Make sure (View > Snap to Guides) is on.
For each of the 4 images:
Select the image in the layers dialogue, then use the Move tool to move it into position.
Create a new image 512x512.
Use (File > Open As Layers) to open your 4 256 x 256 images. Each image will be on its own layer.
(If it is only 1 image that you are displaying 4 times: use Open As Layers to open the 1 image. Then, in the Layers Dialogue, use the Duplicate button to duplicate the image 3 more times.)
Use (Image > Guides) to create 1 vertical and 1 horizontal guide at the 256 pixel position. Make sure (View > Snap to Guides) is on.
For each of the 4 images:
Select the image in the layers dialogue, then use the Move tool to move it into position.