Concretely, the set is laid out onto one canvas with consistent sizing, and the output format is chosen to suit the inputs rather than forcing everything through a lossy encoder. Upload everything you want combined and the result comes back as a single file.
Can I control the order things are joined in?
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Yes — drag the uploaded items into the order you want before starting. Order is taken from the list, not from the filenames, so "IMG_2.jpg" sorting after "IMG_10.jpg" is not a problem you have to solve first.
Does it matter if the inputs are different formats?
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It does. this format is read and written by the same streaming pipeline as everything else we support. Matching inputs take a fast, lossless path; mismatched ones have to be reconciled to a common format, which is slower and costs one encode.
Anything specific to Image when merging?
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Yes — the pipeline reads the real format from the file header rather than the extension, so a mislabelled upload still works. That is worth checking when the inputs did not all come from the same source.
How many files can I combine at once?
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On the free tier a merge accepts two files at a time, which is deliberately higher than the single-file limit on other tools because merging one file is meaningless. A pass removes the cap entirely.
Do the images keep their original quality?
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Combining images places them into one output rather than concatenating the files, so what happens to the pixels depends on the target. Where the output can hold the original encoded pictures — a document carrying one image per page — they are carried across untouched. Where they have to be drawn into a single picture, that costs exactly one encode, not one per file.
