Tumblr lets you edit the HTML of your theme but not individual pages. There is no default option to edit the alt tag of a picture that you post; Tumblr automatically assigns the text associated with the picture as the alt tag.
As far as I know, editing the alt tag is not possible however I was hoping someone might have an answer here.
Best Answer
The short answer is no - Tumblr doesn't let you edit the alt text of your photos.
The longer answer is that it should be possible if you tell Tumblr in Settings that you want to edit your posts using plain text/HTML. Then, create a new text post, and add the photo with a normal
<img>
tag and with whateveralt
text you like. This should work, although users reading your blog from their dashboards instead of your homepage will have to click through to see the image at all.An issue here is that you cannot upload an image to Tumblr using this method - you have to link to an image with the
img
tag, so it must be hosted elsewhere.