Fix Image Export Failures
Separate file-type errors, excessive pixel counts, memory pressure and blocked downloads using a small repeatable diagnostic sequence.
Identify where it failed
Separate three stages: reading the source, preparing the output and saving the result. An unsupported source needs conversion or recovery. A processing failure can require fewer pixels or a smaller batch. A successful export with no saved file needs a download check. Repeating every step without identifying the stage hides the useful clue.
Compressed bytes and pixel count describe different demands. The actual files below have equal dimensions but different byte sizes. Their one-buffer estimates are equal; total browser memory use has not been measured. This is why reducing dimensions can help even when the original file looks small on disk.
Disk size and decoded pixels
These downloadable JPGs have the same dimensions but different encoded sizes. Each needs 4,320,000 bytes for one hypothetical 8-bit RGBA buffer: 1200 × 900 × 4. That is a calculation, not a measurement of total browser memory.
| Sample | Actual file bytes | One RGBA buffer |
|---|---|---|
| Porcelain cup photograph | 47,070 B | 4,320,000 B |
| Seeded random noise | 774,165 B | 4,320,000 B |
A small compressed file can still have many pixels. Decode copies, canvases and thumbnails add overhead. Use dimensions and smaller batches to diagnose a stalled tab; do not infer device limits from this table.
Image sources and reproduction
Photographs: Coffee Cup, The Metropolitan Museum of Art; Coffee cup and coffee bean, mcfoodie. Both are CC0. They are third-party test material, not photographs taken by this project. Pattern, text, transparency and noise fixtures are generated tests.
Measured 2026-10-20 with sharp 0.35.4, libvips 8.18.6, Node 24.13.1. Download all dimensions, byte counts and SHA-256 hashes. Reproduction script.
If selection rejects the file
This tool accepts JPG, PNG and static WebP and checks image headers instead of trusting the extension. Renaming HEIC to JPG does not convert it. Animated PNG/WebP, GIF and SVG are outside its supported scope. Convert a supported copy in a trusted editor, keeping the original.
Image Prep limits inputs to 24 megapixels, 20 MB per file, 20 files and 100 MB total. A file can meet a marketplace's requirements and still exceed these tool limits. If the source will not open in another editor either, recover a complete original rather than repeatedly uploading a damaged copy.
If preparation stalls
Cancel, preserve any successful results and test one failing image by itself. Then reduce output dimensions and close other demanding tabs. Memory pressure depends on device, browser and other activity; a product limit is a safeguard rather than a capacity guarantee.
- Note the failed filename and the exact displayed message.
- Try that file alone using smaller dimensions.
- Compare another supported file at the same settings.
- If both fail, retry in a current browser after reloading and without unrelated tabs.
- If only one source fails, convert it from a complete original and retry.
If the download is missing
Check the browser's downloads list and any save-location prompt. The tool says download requested because it cannot inspect your Downloads folder. If the archive fails, save individual successful images or prepare a smaller batch. Outputs are capped at 12 megapixels each and 100 MB per batch.
If a saved file has the wrong extension, inspect its actual format rather than renaming it to force acceptance. Browser encoding can fall back to PNG; the tool uses the returned MIME type to choose the filename. Open the downloaded file before sending it to a marketplace.
If settings disappear
A private browser window, blocked storage or cleared site data can remove saved settings. You can still use the controls without storing them. Browser settings are not a cross-device account and should not contain confidential product or customer information.
If the problem remains reproducible, report the page, browser, operating system, input type and dimensions, chosen settings and exact error. The linked tracker is public, so provide a non-private test file rather than a customer's photograph.
How this guide was made
Written from the documented sources and downloadable examples on this page. Reference-encoder results explain the file decisions; the final browser output and destination preview still need checking.