Photo Too Large for a Puzzle Maker and How to Reduce It

File size is the storage a picture occupies, measured in bytes, KB, or MB. Pixel dimensions describe its width and height. Two images with identical dimensions can have very different file sizes because their format, compression, and picture content differ.

The current maker rejects supported files larger than 20,971,520 bytes, or 20 × 1024 × 1024. That is 20 MiB, displayed on the site as 20 MB. A file manager may round its size or use decimal MB, so make a copy comfortably below the displayed limit instead of trying to hit the boundary.

Reducing width and height removes pixels. Lowering JPEG quality saves space by discarding some image information. Both can bring the file below the size limit, but check the result before playing. Changing only a print-resolution label while leaving the pixel dimensions unchanged will not meaningfully shrink the image data.

On a Mac, Preview provides the controls you need. Duplicate the original in Finder first, then open that duplicate in Preview. A name such as lake-puzzle-copy makes the working file easy to spot in the chooser.

1. 1

   Reduce the dimensions.

   Choose Tools > Adjust Size. Use pixels for width and height, enable Scale proportionally, and select Resample image. For a large landscape photo, try a width around 2400 pixels. Keep the proportions so people and objects retain their shape.

2. 2

   Export a JPEG copy.

   Choose File > Export, select JPEG, and use the quality control to make a reasonably clear first copy. Save it under a new name. Reopen the saved image and check its file size in Finder with Get Info.

3. 3

   Adjust only as far as needed.

   If the copy remains too large, start again with a fresh duplicate of the original and reduce the dimensions or quality a little further. Once the file fits and important details remain clear, stop. Repeatedly saving the same JPEG makes it harder to compare against a clean starting point.

On another device, use an editor with equivalent resize and export controls. Keep the saved copy on the device from which you will choose it. A renamed .jpg extension does not perform a conversion, and a ZIP archive is not a supported puzzle image.

See Apple’s Preview resizing instructions.

See Apple’s JPEG export instructions.

For this guide, we created an original lakeside test illustration with fine texture and a small sign. It is a synthetic image, not a photograph. Both JPEGs came from the same untouched PNG using a local image script. The quality numbers below describe that encoder’s settings, not exact positions on Preview’s slider.

In Chrome on October 13, 2026, the original triggered the file-size error. JPEG A and JPEG B each passed processing and opened a 12-piece board with the reference image visible.

Both exports keep the house, boat, and mountain outlines easy to recognize. The larger JPEG preserves cleaner sign lettering, so it is the copy we would choose here. This illustration compresses particularly well. A photograph with foliage or grain can produce much larger files at the same settings.

Download JPEG A to inspect the larger copy.

Download JPEG B to compare the smaller copy.

Open the photo puzzle maker and choose the exported copy. Reaching the difficulty chooser confirms that the image passed selection and processing. Choose 12 pieces for a quick check, then open the reference image on the board.

Try your smaller copy in the photo puzzle maker.

Look at one detail you actually need during play. Can you separate the roof from the sky, read an important label, or distinguish the eyes in a portrait? Check the reference at your normal playing size. A tiny thumbnail can hide damage that becomes obvious on the board.

If the size error remains, confirm that you selected the new copy and check its exact byte count. If a smaller file produces a format or processing error, follow that message instead of continuing to shrink it. HEIC conversion has its own troubleshooting steps.

For HEIC conversion errors, use the separate HEIC guide.

Continue with the full photo puzzle tutorial.