frame links problem

[craigo]

i am designing a site with a navigation frame on the left hand side. on the right hand side(main frame)i have thumbnail images. i want to link these images to full size versions but i want these to be full screen. I can manage to do this but i can't put a link back to the original frame layout everything just stays full screen. I have tried all the different target tags that i know of but with no success. I would really appreciate it if somebody could tell me how to do this.

[gizmo]

Would adding a 'Back' button under the picture like so be acceptable ?:

<FORM><INPUT class="back" type="button" VALUE="back" ONCLICK="history.go(-1)"></FORM>

where class "back" defines the text and background colour of the button