Find missing images
This Check finds broken or invalid images. These might be:
- 404 / 410 errors
- Other HTTP error codes
- Malformed URLs
- Non-contactable servers
- URLs with too many chained redirections
- Images that take too long to download
Types of images checked are:
- img tags
- object tags
- css background images
Missing images annoy users. The page loses content and the page layout can also be adversely affected.
Most a 404 errors are caused because the owner of the website where the image is hosted has removed or moved the image. It is recommended you either remove this image from the design of your site or use an alternative image.
Malformed URL errors
Most of the time, malformed URL errors are caused by a typo in your HTML. Try reviewing the image URL to make sure it is valid.
Non-contactable server errors
A server may only be temporarily non-contactable. If you are worried the server is unavailable too often, it is recommended you remove this image from your site.
Configuring this check
Select the Settings link next to the check in the Checks tab or select: Settings > Check settings > Find missing images
Note: De-selecting any of the following may hide other errors.
Find malformed URLs
Check for badly structured URLs (for example full URLs which have a protocol which is not widely recognized)
Find errors contacting remote servers
Stop DeepTrawl from showing a problem when a server cannot be reached over the Internet. This should usually be left on.
An error will be shown if the link times out (the timeout setting is in advanced settings, connection tab).
Error if image download takes longer than x
Shows an error if the download takes longer than the specified time. It's a good idea to set this too a high value; remember DeepTrawl could be taking a lot of your local bandwidth, making the download seem slower.
Follow HTTP redirections and report any errors which occur with any of the redirections or the resource found at the end of the redirection(s).
All redirections are errors
Ignore any HTTP redirections when downloading links. An error will be shown for any redirection when downloading a link.
Error if too many redirections
Switch this off to suppress errors where DeepTrawl could not reach a linked resource because too many redirections were used. For changing the maximum number of redirections, advanced settings, connection tab.
Error HTTP codes
Switch on or off to search for specific HTTP error codes. For instance you may wish to never see errors caused by 401 (unauthorized) HTTP codes.