Stitch Images Together Online
Did you take multiple photos and want to combine them into a panorama? Or you scanned parts of a picture and want to reconstruct the whole image? It can be done easily online!
We will stich our images online in a photo editor Photopea.com. Once you are there, press File - Open, select all images from your computer and open them. They will be displayed in Photopea as separate documents. You can switch between documents by clicking the labels at the top.
Put everything into one document
Now, we need to put all images into a single document (e.g. the first one). Switch to a second document, press Ctrl+A (or Select - All) to select all. Press Ctrl+C (or Edit - Copy) to copy, switch to the first document, and press Ctrl+V (or Edit - Paste) to paste. Copy images from other documents in the same way. The first document will contain each image as a separate layer (the list of layers is on the right side of Photopea).
We need to select all layers. Look at the Layers panel on the right side. Click the bottom-most layer, hold Shift, and click the top-most layer. Selected layers are highlighted. Press Edit - Auto-Align to make Photopea align images with each other. The bottom-most image will stand still, while other images will be moved, rotated and scaled, to create a final result.
Fix edges between images
Once the images are moved and rotated, we can still see differences at places, where two images meet. While all images are still selected, press Edit - Auto-Blend.
Another way is to use the Eraser tool. Press E to switch to the Eraser. Right-click the image and increase the Size and decrease the Hardness of the brush. Click a layer you want to work with (in the Layers panel) and erase the unwanted areas by painting over them.
Now, save your image by pressing File - Export As - JPG. Done! :)