Image watermark

I am trying to create an app for taking picture and add water mark to the picture. I am using image editor to place watermark. It works correctly in my mobile. But when i export and test it in other device, the placement of watermark is changed. I found this happens due to the change of pixel size of the picture.
Is there any ways to make the watermark fixed for any sizes.

Would be nice if you can explain why you have set “global x” and “global y” here, and maybe what they mean. This way we can assign percentage values to the sprite, convert it to pixels for the device, then display the watermark.

For a temporary fix, i made an if clause for three different pixel sizes. The global x and global y are point x and y in the watermark block.
Those points i have tested with various devices.

Would be helpful if you explain me the percentage values in sprite.