- Join Photos in Photoshop
Suppose you want to make a panorama in photoshop by joining two photos, but the lines in the picture do not line up where they will intersect. (See the unmerged photo pair below). Joining them as they are would make the wall behind the fireplace appear to form a corner.
- Step 1
Select two photos with some part of one photo showing part of the same view as in photo two. I.E., there must be some degree of overlap (preferably about 10%). Make the canvas size of pic 1 wide enough to hold the added photo, and paste it in.
- Step 2
Align the photo content. These pics both show perspective lines that will not match up (E.G., Ceiling molding line, floor skirting board line ). To join the pictures successfully you need to make the perspective lines in the photos parallel. Click on the top Ruler and drag down with your cursor — (a blue horizontal line should appear) – position the line on the low end of the ceiling molding. Click the Edit/FreeTransform menu (Ctrl T) and hold down the Ctrl key to drag the top right corner handle down until it lines up with your blue Guide Rule
Repeat the process until all the perpective lines match, then crop the pic to trim the top and bottom edges. (if your version of PShop includes the perpective tool, you might prefer to use that instead of the FreeTransform tool)
- Alternative Step 2
If your Photoshop includes Filter/Distort/Lens Correction, then use this instead, it is faster and easier to line up with the built in grid pattern. Just grab the Horizontal Perspective handle and drag it left until the gridlines and the perspective lines match.
- Step 3
a) Go into Quick Mask and select/draw a rectangle over the area to be merged. b) With foreground Black, and Background White, use the Gradient Tool from left to right and fill the rectangle selection. c) Back out of Quick Mask and invert(Ctrl Shift I) the selection. d) Click Delete. 
- Step 4
Slide the RH pic across to the left onto the LH pic until the images merge.
- There you go, you now know how to stitch together two photos using PShop, where the picture perspective lines DO NOT line up.