If the alt text is still appearing when you try to pin one of your images, the culprit is likely another plugin.
Many plugins that add hover buttons over images force you to select a Pinterest description. These options are generally limited to the post title, the image alt attribute, or a single Pinterest description you set. Thus far, we have not come across any plugins that allow you to use the
data-pin-description for the image (which is what Tasty Pins sets with the Pinterest Text and is the recommend way to set the pin description).
The solution for this issue is to turn off the plugins that add these hover buttons over the images and use the default Tasty Pins hover button.
The Tasty Pins hover button uses the default Pinterest hover button functionality. Benefits of using the default Pinterest save button are as follows:
Duplicate buttons don't show when the user has the Pinterest browser extension installed
You can be sure that the button uses the most up-to-date code and recommendations from Pinterest
Pinterest optimizes their save buttons for user interaction – potential for more pins
No conflicts with the alt text and the Pinterest text