Want to learn about these content should start from nothing.

From the customer license agreement:

�If and where commercially reasonable, the use of Visual Content in Merchandise or an audio-visual production shall be accompanied by a credit to Shutterstock in substantially the following form:

"Image(s) or Footage (as applicable), used under license from Shutterstock.com"

Credit attributions are not required in connection with any other use of Images unless another stock content provided is afforded credit in connection with the same use.

In all cases the credit and attribution shall be of such size, color and prominence so as to be clearly and easily readable by the unaided eye.�

Usually film contracts have an explicit section that details how credit will be given for any labor or contributed materials.

If the footage and Shutterstock were not in the end credits of the film already, it�s doubtful they want them on the IMDB page, as they may then need to credit others.

They are definitely not required to credit you as the artist since they purchased it under the above license.

Films are only required to credit when contractually obligated or if they are claiming Fair Use. Neither apply here.

All that being said - you could  just try and see what happens. Probably not a huge deal.

I'd just submit your info to IMDB.  Couldn't hurt.  I did this a few years ago for old video editing and motion graphic credits and they were added to my profile.