Today in the chatroom, we were discussing the practice of adding meaningful alt text to images on the web. Alt text is displayed when the image cannot be displayed and is therefore especially important for visually impaired readers who use a screen-reading device to tell them what's on the page.
The convenient tool provided by Stack Exchange for adding an image to a post automatically adds a default alt text of “enter image description here," leaving the user to replace that default in the content of the post with a meaningful alt text1. As a result, about half of the posts with images in them on Mi Yodeya contain this default alt text (or the previous default, "alt text")2. Thanks to Mi Yodeya's relatively small size and relatively infrequent use of images, the number of such posts is only about 130, plus 25 here on Meta.
Call to action
Let's work together to add useful alt texts to every post that currently features a useless default value. Besides the various benefits in terms of accessibility, searchability, etc., we can be motivated by the requirement for sensitivity to the needs of visually impaired people implied by the plain meaning of Vayikra 19:143:
לֹא־תְקַלֵּ֣ל חֵרֵ֔שׁ וְלִפְנֵ֣י עִוֵּ֔ר לֹ֥א תִתֵּ֖ן מִכְשֹׁ֑ל וְיָרֵ֥אתָ מֵּאֱלֹהֶ֖יךָ אֲנִ֥י יְהוָֽה׃
Thou shalt not curse the deaf, nor put a stumbling-block before the blind, but thou shalt fear thy God: I am the LORD.
How to help
Choose a post to work on, and check this list (Mi Yodeya) or this one (Meta) to see if it's already on the "Done" list. (The query results aren't good enough for this, since the underlying data is only updated weekly.) If not, click on the post link.
Edit the post, and resolve all instances of "enter image description here" or "alt text" in one of the following ways:
If the entire post is without value to Mi Yodeya, flag it for deletion.
If the image adds no value at all to the post, edit it out.
If the image is a picture of text, serving solely in lieu of a quotation, either replace the image with a block quotation of the text, or, if there's particular value in the way the text is displayed in the image, use, as alt text, the text shown in the image.
If the image is purely a decorative way of representing text that's right next to it, e.g. a "Search" button next to the word "Search," use an empty alt text:
If the image is the only content of a link, use an alt text that describes the target of the link.
Otherwise, use an alt text that describes the information in the image that's relevant to the context. For example, for the Mi Yodeya logo, in most contexts, you would put "Mi Yodeya logo," not "tree with a question mark in the middle, in the vague shape of a Star of David."
Do not include the words "image of" in your description. As per @doppelgreener, screen readers will read out "Image: (whatever you use for its alt text)," so this is redundant.
While you're in there, if you see other ways you can improve the post, make those edits, too. In particular, if the image would benefit from mouseover text, add that.
In your edit summary, make reference to the fact that you're fixing the alt text.
Go back to the relevant list, cut the link for the post you edited from the "To Do" list, and paste it to the "Done" list.
1. I endorse this proposal to augment the tool.
2. Very anecdotal evidence suggests that this ratio is not atypical on Stack Exchange.
3. Despite the fact that this verse's standard Halachic interpretation is more broad, we might as well be inspired by the plain meaning as well.