Perhaps I don't know how to do this properly, but it looks like image_styles are not integrated into the core token module.
With out image styles in tokens it's very hard to use images in things like email templates.
I would request that code similar to this contrib module is added to core, as both token and image_styles are also in core.
Closed: outdated
7.0 ⚰️
token system
With
Drupal 7 reaching End Of Life in January 2025 →
, this issue is now outdated. Drupal 8+ supports image style tokens via the Token module using a token format along the lines of, say, [node:field_image:thumbnail:url].