Keep in mind that this is area-level tiling as an alternate way to present wiki page listings (see the OP). Even though a gallery add-on was shown as an example of what tiling is, the feature is not intended to function as an image gallery.
I am trying to get something like what you are describing now, but it seems to be unfeasible below 150px:
This uses the page's "icon" field and needs to be tailored for that. Icons are generally small, square images. Upscaling them beyond a certain point starts not looking great. Other times, the icon will just be an FA character. It may not look great to have 50 200px font-awesome characters tiled on the page, especially when most of them are the same.
So we need to strike a balance of what will look good when there is a mixture of font-based and image-based icons on the same page. We are testing this in our Image area because it has a high number of customized icons and would give a better idea of how it would look if icons were used to their fullest potential. But in many cases, it will not be used for an area full of images, even if that is what the OP hopes.
We have to be careful how we deal with prefixes. In VaultWiki 4, they do not refer to a wiki function or a wiki content type that VaultWiki can figure out. They are a meaningful part of the title. The example only uses "Image" on that page, but this feature could be used in any area, with any mixtures of prefixes. What if we have 5 prefixes "Wolves", "Fish", "Fruit", "Person", etc? An FA "image" icon would not make sense. And with so many prefixes on the same page, removing or hiding the prefix might become confusing to the user.
Since the tile is for page listings, the title is still the most important part of the listing. For a more typical case, I have now enabled it in the Demo area:
https://www.vaultwiki.org/demo?do=list