Hi Dagur,
Let's me try to rewrite a bit...
In Cognos Analytics, you will create an HTML element that will be : '<a href="' + [Product image] + '" target="_blank">' where [Product image] is a valid URL.
Create a list report.
Drag [Product] and [Product image] in this list.

I don't have Cognos Analytics v11.1.7 available, so I can create a screenshot for the next advice.
To unlock a report, click the More icon
and then click Locked. All layout objects in a report are unlocked. Please follow the document from https://www.ibm.com/docs/en/cognos-analytics/11.1.x?topic=reporting-report-objects.
You will drag an HTML element to the left of your image.

This HTML element should be a Data Item Value with the following value :
'<a href="' + [Product image] + '" target="_blank">'
Then you drag again a new HTML element to the right of this image. Source type is Text with the following value :
</a>

Run your report, if you click on the image, it will open a new tab in HTML output. If you will PDF output, you will see the image but there is no link in this page.
Note : @Dagur Egonsson, send me a message if you need more help.
Best regards,
Patrick Neveu, IBM Champion