Dezoomify FAQ
Make sure you are using a recent web browser. Any recent version of Firefox or Chrome should work. Copy and paste the url of the webpage that contains your zoomable image to the text field on dezoomify, then press enter, and that should be all. Zoomify will automatically detect what kind of zoomable image it is, and how to download it. Once the image is fully loaded, right-click on it, and choose Save as. It may take some time, but your browser should eventually open a file dialog, asking you where you want to save the image, and save it (as a PNG file).
If it doesn't work, see the other questions below.
In order to download an image, dezoomify needs a small meta-information file. Sometimes the URL of this file can be found automatically just by looking at the image viewer webpage, sometimes it cannot.
New : There is now a browser extension that can find these meta-information files automatically. It is currently in beta. Download the dezoomify firefox extension or the dezoomify chrome extension, and help improving it by reporting issues.
In that case, you can try to find this URL yourself:
- In the browser window that contains your zoomable image, open your browser's network inspector (Tools > Web development > Network in firefox).
- Select XHR at the top of the inspector.
- Refresh the page (press F5). If not done already, display the zoomable image inside the page.
- You will see all the resources loaded by the page appear in the network inspector. Search for the image information file. it's usually a small (< 5 Kb)
.json,.xml, or.dzifile. For zoomify, this file is called ImageProperties.xml. - Copy the URL of this small file.
- Paste the the URL to this information file to dezoomify. It should then be able to load your image.
A dezoomer is a small part of dezoomify that handles a specific zoomable image format.
The radio boxes allow you to choose the dezoomer used for your image.
When Select automatically does not work, you can try to manually find out which image format was used for your image.
Sometimes, the name of the image format will appear along with the image viewer.
Sometimes, it doesn't. If so, you can try to right-click the zoomable image from your browser, then choose Inspect this element, and try to find clues about the dezoomer used in the code that appears. Alternatively,you can view the source code of the page using Ctrl-U on most browsers.
Yes, there is!
Dezoomify has a generic dezoomer, that tries to be clever and guess how many tiles there are, and stitch them together.
If your image is composed of multiple tiles, find the url of the tiles. For instance, you can use the Network inspector of your browser (Ctrl-Shift-Q on Firefox). Once you found an image url, try to spot inside it the coordinates of the tile inside the global image. Replace the horizontal coordinate by {{X}} and the vertical coordinate by {{Y}}. See the detailed tutorial for more information.
Paste the resulting url in dezoomify. The generic dezoomer should be able to dezoom it.
There is a tutorial video about the generic dezoomer on youtube: https://youtu.be/SY1dZe7MrUQ.
I see an error saying Check that your internet connection is working and that you can access this URL: http://...
Google chrome tries to prevent HTTPS websites to load images coming from HTTP sites (see their justification). Since dezoomify itself is served over HTTPS, if you try to load images coming from old insecure websites that do not support HTTPS, dezoomify will display the Unable to load tile error.
You can manually add dezoomify to the list of HTTPS sites authorized to load HTTP content by updating your chrome preferences in
chrome://settings/content/insecureContent
It might happen that the image format is a little unconventional, and that the generic dezoomer doesn't work. You can try dezoomify-rs, a command-line desktop application that allows you to specify a custom image tiling logic.
In this case, a new dezoomer will have to be written. You may want to try and write your own dezoomer.
If your image is very large, it might happen that your web browser will display it, but crash or do nothing when you right-click and select "Save image as". Chrome in particular is known to be affected by this bug. There is nothing you can do about that, but use another browser. Firefox solved this bug not long ago, so you should be able to save even quite large images with it. In firefox, if the image is very large, the browser will freeze for a few seconds when you click "Save image as", but everything will work then.
See the very large images wiki page.
If you see a working progress bar, and no error message, but the image does not appear, this might be due to your browser limiting the maximum amount of memory it can allocate for any surface that will be drawn on screen (see this firefox bug for instance). This limitation is, at the time of writing, set to 500.000.000 on firefox. If the result of the height of your image x the width of your image x 4 is over this value, firefox will refuse to allocate memory for it, and display a white canvas. Other browsers have different default values, but all of them limit the maximum size for a canvas.
There are two ways of fixing this.
You can tell dezoomify to scale the image down as it downloads it. The resulting image will be smaller, but this has the advantage of not having to play with the browser's settings, making it unstable. Open your browser's console and type:
UI.MAX_CANVAS_AREA = 67108864On firefox, you can change this limit and thus display the image, but be warned, it's dangerous: if the limit is too low, your browser will refuse to render anything, and if it's too high, its big allocations may crash not only firefox, but also your graphic card driver.
To change this limit, in firefox, open a new page, and type about:config in the address bar. Click I accept the risk. Right-click anywhere in the list that appears, and choose New > Integer. Set the preference name to gfx.max-alloc-size, and the value to, for instance 2000000000. Resatart firefox. I would strongly advise that you do it only if you really need it, and set the value back to 500000000 once you've downloaded your image.
See the very large images wiki page.
Good news: I do now accept donations ! See my sponsoring page. Funding dezoomify could allow to pay for a better web host, a domain name, and the development of new features.
First, try to desactivate all your browser plugins. Some poorly coded plugins may prevent dezoomify from working. If it still doesn't work, you may have discovered a bug in dezoomify. So you should open an issue here. Please include all the information that may help me solve your issue :
- the URL of the web page containing your image
- if you get a red error message, copy & paste it.
- the name and version of your web browser
- if your problem is hard to describe, you can include one or several screenshots.
And if you know javascript, your contributions are welcome 👍