imageCompare is a webpage that allows you to compare two sides of an image pasted from the clipboard.
https://asteriskman7.github.io/imageCompare
After pasting the image from the clipboard into the textbox, drag the image in the result window below to get an approximate alignment. (Alternately, left click the reference image to set the left image reference line and right click the reference image to set the right image reference line).
To make single pixel adjustments as well as updating the vertical alignment, you can use the left/right/y text boxes or press the optimize button which will attempt to find the best alignment. Range sets how far to look for better placements (It gets slow fast so don't go too large.) Speed sets the max number of pixels to skip when checking for optimal placement. Multiple skip distances are actually used to avoid aliasing effects.
After alignment, the 2nd image will show differences while common features will be black. Moving the mouse cursor on either the reference images or the comparison image will also show a cursor on the other image in the equivalent location(s).
The third image allows sliding between the left and right images which may make some differences easier to see.
(The image used in this example is from Muband at Japanese Wikipedia and subject to Creative Commons Attribution-Share Alike 3.0 Unported license)