Altviewer provides an easy way of reviewing alternative text description or "alt text" from thumbnails, images, and videos. Previously, the only ways to checking alt text was install addons, examining the source code, or turning off images. With Altviewer there’s no installation hassle and you can compare the alt text side-by-side with the image it describes.
I have updated the software to better identify different types of default alt text. It will classify into the following types:
|Default alt text||Alt text was automatically produced by MediaWiki. Thumbnails and videos usually default to blank; inline images is usually the filename.|
|Caption alt||Special case for inline images, if only a caption is specified it is used as both the image's alt attribute and the link's title attribute. (NOTE: Generally screen readers will fallback to reading the title attribute if the alt attribute is missing)|
|Unlinked||Appear if dimensions are larger than 100px on a side, was not generated MediaWiki, and was not match by any of patterns.|