Lots and lots of people ask this question... but think about it....

If I answered... "Fifty links is too many.".....   and you listened.....

.... but all of the websites on the first page of Google for your keyword were naturally earning 200 per week.... you could work forever and never make first page.

You need information about relative link velocity and link quality.

It is possible that you and three other people working would never be able to create enough links.

The hard bit is that nobody on mobile devices are using sidebar and that means people visit one page and leave without exploring any additional resources.

Go to a few of your pages and find opportunities to link to your own content.

• As the hypertext that wikipedia overuses in some people's opinion.
• In little boxes that float to the left side of your mobile pages (use images and text that elicit clicks)
• As a large menu of related articles at the bottom of your page (look at the provocative images presented in the Outbrain, Taboola, and similar widgets - you don't have to be nasty or naughty like some of them - there are many other ways to earn a click)
• in a search box at the bottom of your article and invite readers to use it
• you don't need a sidebar to entice people to visit another page... just show them what you have that is relevant, what is popular, what is new, what is outrageous - depending upon your audience.
• duplicate your menu at bottom of the page

If your freelancers obtained "royalty free" images then they will likely have a receipt proving that they paid a fee for each image that was granted a royalty free license.  If they obtained other forms of license or permission they should have that neatly logged in a spreadsheet or in the form of email messages.  That is where I would start with this.

If you don't have any documentation then it is going to be really hard and really costly to go backwards to determine where each image came from and if proper permissions and licenses were obtained.  That might cost more than doing the work over again.  If I was in this situation, I would start over on this project.

If you are getting into the business of using the images of others then a good education in copyright, fair use, licensing, permissions, and proper documentation is essential.  In addition to you having this information and knowledge, anyone who works for you must have it because the problems of infringement will be yours and not theirs.  Lots of people run wild and rampant when collecting images for their websites or client websites.  They simply don't understand copyright law or the problem with ignorance.

Will people get in touch with you before filing a DMCA or filing a copyright infringement lawsuit?   They might or they might not.  If they think that your website is run by scofflaw organization with few assets then they will probably just file DMCAs with search engines and hosting companies.  They might also file complaints to Adsense and other income sources.  Successful DMCA and Adsense complaints will put the infringer out of business.  I make lots of these complaints against infringers and have a system in place to do them quickly and efficiently.

If your website appears to be run by a substantive company and the person who's images you infringed is a decent and patient, they might send you an informal infringement notice, give you a chance to fix it, and then file DMCA and income source complaints if you don't respond quickly.  Or, they might send you a bill for your past use of the image and a license agreement for use of the image going forward.   If you have stolen a lot of their images or you have a person who stands firmly on their intellectual property, they could go straight to a lawsuit or other legal remedy.

The owner of the images enjoys the ability to chose their methods of dealing with you.

It all depends on the quality....

... if this content is best-on-the-web then publish it only on your site but promote it everywhere

... if this content is really good then publish it only on your site, promote it there conspicuously, promote it to your closest allies

... if this content is low quality then offer it to your competitor to post on his website

I run my buttons through forms.  Thus no links and no "product pages" generated by the shopping cart.

This enables me to produce most of my sales from minor category pages with multiple products or multiple varieties of single products.  I believe that these single pages compete better in the search engines that four or more separate pages.  I also believe that they result in more items being added to the cart - because the customer sees the variety.

Eliminating all of those product pages gives me a much smaller and more compact site that I believe competes better in the SERPs.  It also enables me to produce custom product pages that are not possible through the cart's product page template.  They can be optimized like finely crafted arrows instead of being made by a cookie cutter program.

If you don't know how to produce form code, ask your cart provider for help.   My code looks something like this.

<form action="https://secure.example.com/cgi-bin/addtocart?MERCHANTID=EGOL&ADD=id-tool-225" method="post"><input type="<a class="attribute-value">image</a>" src="/add-to-cart.gif" width="<a class="attribute-value">105</a>" height="<a class="attribute-value">35</a>" border="<a class="attribute-value">0</a>"  align="<a class="attribute-value">middle</a>"></form>