I was looking through the Bigstock Standard license, and here's how it opens:

"Use of image files
Bigstock licenses to you the use of image files only as provided herein  on a nonexclusive and nontransferable basis upon payment of the required fees. All other rights to the image files and any accompanying materials such as copyright are retained by Bigstock and its members. The license granted to you is limited to one usage per download. For example, if an image is used in a website design and in a business card design, this is considered two usages for which the image license must  be purchased two times. Using an image in multiple products without purchasing the licenses for each usage violates this Agreement."

I've never seen wording related to the "one use per download" before, and this has never been my impression about royalty-free usage.

I didn't see anything like this in other agency terms and it seems like a significant restriction. Any thoughts?

Policing this is impossible at micro prices, and especially when people might post their images to many agencies.

I remember a discussion in the past about this, indeed BigStock puts this restriction - it would be much more edible this way - but it is actually impossible to enforce.

Like TS saying buyers can only use them during the duration of their subscription. How could that every be policed?
Added; ..."at micro prices"

That would not be "royalty free", and thus their claims their content is licensed royalty free would be false advertising.

"This agreement requires you to  re-purchase the image file photo for each new usage. "

That was exactly my impression, and thus my confusion!

The "false advertising"  argument assumes there is a standard definition of "royalty free", which of course there isn't. All the microstock licenses are limited in ways that traditional RF licenses aren't - the IS "royalty free" license is limited to less than 500,000 impressions and on available uses, so doesn't really meet the traditional definition of royalty free either.

At it's least common denominator, "royalty free" means you are able to use it more than once without paying additional royalties.  That's pretty non-negotiable.  Otherwise, the words have no meaning.   A "royalty free" one use license would mean you didn't pay to license it in the first place.

Has anyone ever asked about this? It seems like now that they are owned by Shutterstock, this would get updated. I doubt SS would push this type of language in a current license.