Troubleshooting
Find the symptom below and try its next step.
No image found
Use the address of the page showing the image, not a search page. Try the extension after the viewer has loaded, or find the description address manually.
Forbidden or unauthorized errors
If the page requires sign-in, use the extension while signed in. Desktop cannot reuse your browser login, and copying an address alone does not transfer that access.
Some servers require the viewer page as the request's referrer. In desktop,
set that request header; on CLI use
-H "Referer: https://the-site.example/viewer". If the site's own viewer also
fails, resolve access there first. Never share passwords, cookies, or sessions.
The image appears blank, or the browser slows to a halt
Use desktop for images beyond browser
limits, or CLI --max-width for a smaller copy. Try maximum attempts the
full resolution but cannot remove browser limits. The extension has the same
image-size limits as the website.
The image is visible but the browser cannot save it
The browser may display an image too large to encode, or the site may permit display without readable pixels. Try desktop; for source-session access, try the extension. Dezoomify labels display-only output rather than claiming it saved.
The save stopped partway
Temporary tile failures retry automatically. If those retries are exhausted,
the website, extension, and desktop pause and offer Retry once more or
Cancel. Retrying keeps successfully downloaded tiles. The job waits for your
answer; it does not automatically save an incomplete image. Permanent tile
failures stop the job without saving. CLI stops when its retry budget is exhausted;
increase --retries for transient failures or restart using cached tiles.
For native downloads, repeat the job to reuse cached tiles; see resuming. If the source image changed, remove its cached tiles before retrying. Browser jobs do not use that native disk cache; reloading stops the current run.
The output name is rejected
Use .png, .jpg/.jpeg, .tif/.tiff, .zif, .webp, .avif, or .iiif;
an extensionless path creates an IIIF folder. Other extensions are rejected.
JPEG and AVIF are limited to 65,535 pixels per side and WebP to 16,383. Use PNG, TIFF,
ZIF, or IIIF for larger dimensions. Choose an unused IIIF destination;
--overwrite does not replace an existing directory.
The site only works without encryption
Browsers block insecure resources from secure pages. Try desktop, which can fetch the source site's ordinary HTTP resources.
The site limited requests for that image
Wait before retrying. On CLI, reduce concurrency or increase pacing with the
options in dezoomify --help. Changing apps does not remove the site's limit.
The site asks you to wait a few minutes
Follow request-limit advice above.
The image shows but cannot be saved
Follow visible-image advice above.
Sending a signed-in image to another app asks for approval
Review any proposed handoff before accepting. Desktop does not receive your browser credentials, so a signed-in image may still require the extension. See extension data use.
Still stuck?
Open Technical details & logs to copy or save a report or prepare an issue draft. Reports can contain sensitive addresses or settings: review them before sharing. Include the viewing page, app, error, and a screenshot in a GitHub issue.