Views: displaying a field from a vocabulary based on the name
If I understand question aright, you need to use a Relationship in your View.


Under the Advanced section (just below contextual filters) click 'Add' to add a Relationship
Select the field in your node for the relevant term reference, e.g. a field labelled 'Tags' and with a machine name 'field_tags' would appear as Content: Tags (field_tags) in the list that is shown when you select 'Add'
The default configuration should be fine for the use case at hand, so in the next dialog box it should be OK to simply select 'Apply'. (In some cases you do want to tick Require this relationship.)
Go to Add fields and add a new field. Find the image field in your taxonomy. If the taxonomy is called Tags and the field labelled 'Image', it'll look like: Taxonomy term: Image Appears in: taxonomy_term:tags. Select this and click on 'Apply', Then click on 'Add and configure fields'
When you are in the configure dialog you'll see an indication that a relationship is being used. It'll look something like this:





Configure as required and apply. In your fields list it'll look something like this:




What these steps do is say that you want to use the field in the node that contains the taxonomy term to bridge to the fields in the particular taxonomy vocabulary item. Having added the relationship you can now add fields that call upon it. That, if I understand the question, is what is needed here. And, again, if I've understood aright, no need for contextual filters - at least not to get the image from the taxonomy into your view.

These steps apply to Views 7.x-3.5. (In pre 3.5 versions, or perhaps bit further back,  the relationship set up was a bit more complex, but it's now more streamlined.)