Yes, "alt" attribute is for short descriptions. From the w3.org site:
"The alt text should be the most concise description possible of the image’s purpose. If anything more than a short phrase or sentence is needed, it would be better to use one of the long description methods discussed in complex images."
The alternatives for long descriptions are the "longdesc" attribute, "figure" with "figcaption" tag or the "aria-describedby".
"The alt text should be the most concise description possible of the image’s purpose. If anything more than a short phrase or sentence is needed, it would be better to use one of the long description methods discussed in complex images."
The alternatives for long descriptions are the "longdesc" attribute, "figure" with "figcaption" tag or the "aria-describedby".
https://www.w3.org/WAI/tutorials/images/complex/