If the two images are so harmonious that they ask for a connection, it is not worth it just like that. You can create a single whole from two pictures using Adobe Photoshop.
Necessary
Adobe Photoshop
Instructions
Step 1
Launch Adobe Photoshop and open the necessary images: click the menu item "File"> "Open" or use the hotkeys Ctrl + O. In the new window, select the files you want and click "Open". If the photos are in different folders, repeat these steps.
Step 2
Determine the size of these pictures: activate each of them one by one and press the Alt + Ctrl + I hotkeys. Create a new document: menu item "File"> "New" or hotkeys Ctrl + N. In the "Width" and "Height" fields, specify such parameters so that both pictures will eventually fit onto the created document. Click OK.
Step 3
Select the Move tool (hotkey V) and drag both pictures onto the newly created document. Use the same tool to combine the images according to your idea. To select this or that layer, and pictures after moving to a new document become layers, use the list of layers in the "Layers" window. If not, press F7. Merge the image layers. To do this, select both of them, right-click on them and in the menu that appears, click on (Merge layers). As a result, you have a kind of unified composition.
Step 4
Create another document and size it as you think the composition will fit perfectly. Drag the composition onto the newly created document. Repeat these steps until, i.e. create a new document and drag the composition onto it until the dimensions of the composition and the document match.
Step 5
To save the result, select the document with the best option and click the main menu item "File"> "Save as" or hotkeys Ctrl + Shift + S. In the window that opens, specify the file name, path, format and click "Save".
