Such photographs will be covered by copyright laws; more specifically, "work for hire" issues. (search the Internet use "work for hire" key words and you will find lots of info).
Works for Hire - If a work is made for hire within the meaning of the Copyright Act, the employer or other persons for whom the work was prepared is deemed the author for copyright purposes and is the initial owner of the copyright.
If you have a contract with the phrase "This is a work for hire" and employer retains all copyrights in any works created by the employee", (or something similar) then the issue is settled.
With no "work for hire" Contract . . . Two tests.
(1) Work prepared by an employee within the scope of his employment
IF the person doing the work is an employee within the meaning of the common law, and the work was done within the scope of the his/her employment, then the work is a work for hire and the employer owns the copyright. Lots of factors to consider to determine if a person is an employee under common law including:
(i) The level of skill required to do the work (more skill, more likely independent);
(ii) The source of the instrumentalities and tools used to do the work. (worker supplies tools, more likely independent);
(iii) The location of the work (if the work is done on the worker premises (not employer’s), (worker more likely independent);
(iv) Duration of the relationship;
(v) Whether the hiring party has the right to assign additional projects to the worker (if so, worker more likely to be an employee);
(vi) The extent of the worker’s discretion over when and how long to work (more discretion, more likely to be an independent);
(vii) The method of payment (is worker paid the same manner as employees);
(viii) The worker’s role in hiring and paying assistants.
(2) Specially ordered or commissioned works -
Works created by independent contractors may be works for hire only if two conditions are satisfied.
(i) the work must fit into one of nine enumerated categories of works.
(ii) the parties must expressly agree in a written, signed instrument that the work will be considered a work made for hire.
Your situation seems to fall under 2(ii).
Thus, if you want to retain ownership of the copyrights that attach to creative works such as photographs, you need a written contract that says the work will be considered a work made for hire.
If you sign the agreement you presented above, you will not own the copyrights in the works and you will not be able to legally make any material changes to the works (i.e. derivative works) and you can only use them for the purpose they were created.
In contrast, with a work for hire agreement, you own the copyrights in the images and you can modify them and use the in just about anyway you want and resale them.
IF there is nothing special about the model or the photographer, then I would insist on a "work for hire" contract or find models/photographers that will.
Otherwise you own little and you are at their mercy for any future use of the works.