JPG to PDF troubleshooting: rejected files, sideways photos, and oversized output

JPG to PDF runs entirely in your browser — your images are never uploaded — so most problems come down to the files themselves or the options you picked. Here are the common ones and how to fix them.

"Those don't look like JPG or PNG images"

Cause: The tool accepts only JPG and PNG — the two formats a PDF can embed directly. Anything else is rejected: iPhone photos saved as HEIC, plus WebP, GIF, TIFF, and PDFs themselves. One catch: this same message also appears when every file in the drop was a real JPG or PNG but over the 30 MB size cap — so if your files are the right format, check their sizes (next section).

1. Convert the files to JPG or PNG first. On an iPhone, sharing or exporting a photo usually produces a JPEG automatically; to make the camera shoot JPEG in the future, set Settings, then Camera, then Formats to "Most Compatible".
2. On a computer, open the image in any editor or viewer (Preview, Photos, Paint) and export or "Save as" JPEG or PNG.
3. Add the converted files again. Screenshots are already PNG on every major platform, so they work as-is.

"Skipped N files — only JPG/PNG under 30 MB are added"

Cause: Each image must be under 30 MB. The whole conversion happens in your browser's memory, so the cap keeps a drop of giant files from crashing the tab. (This message also appears when a mixed drop contained non-JPG/PNG files — the count covers both.)

1. Check which files are missing from the list — the accepted ones were added normally.
2. Re-export any oversized image at a lower resolution or quality. Almost all camera photos are well under 30 MB; the usual culprits are scans saved at very high DPI or uncompressed exports.

"You can add up to 100 images at once"

Cause: A PDF build is capped at 100 images (a 100-page PDF). Every image is held in memory and embedded on your device, so an unbounded drop of hundreds of photos could exhaust the tab, especially on a phone. If you drop more than fit, you'll see "Added the first N — up to 100 images per PDF. Convert the rest in a second batch."

1. Convert in batches of up to 100 images each.
2. Merge the resulting PDFs with Pages — it accepts multiple PDFs (and images) and combines them in your browser.

A photo comes out sideways or upside down

Cause: Phone cameras often store the pixels unrotated and record the intended rotation in an EXIF tag. AttachKit reads that tag and bakes the rotation into the pixels before embedding, so photos normally land upright. If one still comes out sideways, its rotation metadata is unusual or the browser couldn't decode the file, and the original bytes were used as a fallback.

1. Open the photo in any image editor, rotate it if needed (or just re-save it), and export as JPEG — that writes the rotation into the pixels themselves.
2. Remove the sideways image from the list and add the re-saved copy.
3. Note that the Portrait and Landscape options (shown for A4 and Letter) change the page shape, not the image rotation — they won't fix a sideways photo.

"Couldn't build the PDF — one of the images may be corrupted or in an unsupported format."

Cause: One of the images couldn't be decoded or embedded. Typical culprits: a download or transfer that truncated the file, an unusual or damaged encoding, or a file that isn't really an image but was renamed to .jpg or .png.

1. Find the culprit by removing images and clicking Create PDF again — removing half at a time narrows it down quickly.
2. Open the failing file in an image editor and re-export it as a standard JPEG or PNG, then add the fresh copy.
3. If a file that opens fine everywhere else still fails here, report it — that's a case the team wants to see.

The PDF is much bigger than expected

Cause: Images are embedded at their original resolution. JPEGs go in essentially as-is (no recompression, unless an EXIF rotation had to be baked in), and PNG is lossless — so large screenshots and high-resolution photos stay large in the PDF.

1. Resize or re-export the images at a lower resolution before converting, or
2. Run the finished PDF through Compress and choose its "Make it smaller (flatten)" mode — it re-renders pages as downsampled images, which is exactly right for a photo-only PDF.

Pages are physically huge (or tiny) with "Fit to image"

Cause: Fit to image makes each page exactly the image's pixel dimensions at 72 points per inch — so a 4,000-pixel-wide photo becomes a roughly 55-inch-wide page. Viewers zoom to fit so it looks fine on screen, but printers will have to scale it drastically.

1. Pick A4 or Letter instead — the image is centered on a standard page with a small margin, scaled to fit without distortion.
2. Leave orientation on Auto so wide images get landscape pages and tall ones get portrait.
3. Click Create PDF again — changing the page size always requires a rebuild.

The build is slow or the tab feels stuck

Cause: All the work happens on your device, not on a server. Dozens of large photos mean a lot of decoding and embedding in the tab's memory.

1. Wait for the Building… button to finish — big batches take a while even when the page looks quiet.
2. Close other heavy tabs, especially on phones and low-RAM machines.
3. Convert in smaller batches and merge the results with Pages.

Still stuck?

If none of these match what you're seeing, contact support and describe what happened. Your images never leave your browser, so support can't see them — include how many images you added, their formats and rough sizes, and which page size you picked.