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Chemistry LibreTexts

4.6: Adding Alt-Texts

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    Adding alt-texts descriptors to images on the LibreTexts is critical to satisfy Search Engine Optimization and also accessibility to screen-readers for students with limited visual skills. For information regarding alt-texts check out these pages.

    There are two approaches to adding alt-text to the images and tables of the LibreTexts depending if the text needs to be construction or already exists.

    Approach 1: Adding Existing alt-text text to images

    This is the easiest approach, which is largely a cut-paste approach. While this approach works best on a two-screen system, it can work fine enough for multiple tags on a single browser/screen. There are three steps: Prepare, Copy and Paste:


    • Paste: Then go to the corresponding LibreTexts page and "edit" the page and double-click on the corresponding image.


    • A popup window will give you the option to add alt-text (by pasting) into the page.


    • Paste the text (like above) and then press "Save Image".

    Cycle through all the images on the page and then save the entire page "save" on the editor tool bar (far left).

    Approach 2: Writing and Adding alt-text text to images

    This approach is similar, but require crafting a proper alt-text before pasting into the image properties box. The protocols for formulating "good" alt-texts will be forthcoming.

    Best Practices for Alt-Texts

    • Keep alt text limited to 144 characters.
    • Create caption for content over 144 characters.
      • Blank alt tag (decorative) should be used for images that carry no useful information.
    • Do not create alt tags for images discussed on page, mark as “decorative”.

    Some other issues to be aware of:

    • Tables of information should not be posted as images and needs to be recreated on the page.

    4.6: Adding Alt-Texts is shared under a CC BY 1.3 license and was authored, remixed, and/or curated by LibreTexts.

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