All of my themes and add on blocks ( even the free ones ) have free support so no extended license is needed, ever.
On the base elemental install of concrete5 on the beautiful blog page, if you click the image it enlarges. I took that code and wrapped it in an independent block for your images.
This block wraps your image in the approved <figure> wrapper with <figcaption> used for the caption if you desire.
The core install code is obtuse. This one isn't.
To see an amazing demonstration of this block please visit the demo page.