Image File "Merging" These are image files. Each file renders an image when loaded in any graphics editor or viewer from the code in the file. The image file reader interprets the JPG code to produce the image. What Is Merge? A "merge" process as I understand it, is putting two or more files together to produce one. It works for text files because it's text. The smallest component of a text file is a letter. You can merge two columns of data to produce one list. If you merged together the code for two JPGs at the binary level (not knowing specifics of JPG code), I am not sure what you would get. What Are Your Requirements? Do you want all images to appear together in one file? Like in a mosaic or quilt? That's what I imagine when you ask about merging two images. You use a graphic editor to edit graphics files. There are very cool multi-image mosaic projects out there. Is that what you want to do? Quick Image Editing How-To I presume here is that you want your collection of images to appear in one image file. First, consult your image editor for instructions how to paste up more than one image file. Each editor will have specific steps and menu options. Most take time to master. I have worked with Windows Paint since when it was new so I am best with that. Others use Photoshop. GIMP is also a good editor, but I rate it as more advanced and will require time with the tutorial before starting to use it. This type of computer skill requires stepping back and learning a new skill. It may take a few hours or a few days before you can complete the task you have in mind. It will also depend upon your operating system, the graphics app you are using, your computer system and your screen. What I do (with Windows Paint) is start with a new page, change size to fit all images, use "Paste From" to find and paste images from my computer, arrange images and save. One tip (if you are really new at this) is to learn to use the Zoom tool to adjust view so that you can arrange your images. Details to consider. Sizes of images Resolutions of images Portrait or landscape How image will be used (art, advertising, website, print-making, etc.) It's best if you have a large screen if you are seriously into graphics editing as a profession or even a hobby. Your computer should also be up to the task of loading and rendering images. Hope this helps. Please include more specifics about what you want to achieve, your skill level and your system next time you ask about how to complete a task on the computer.
This is really a first step, the first steps of learning a new skill.