How to specify in presentation that permission to use a particular image is taken?
You can cite it a number of ways. I usually do this:

Right below the image, (Smith et al. 1998) if it's a paper where the image comes from. Then at the end of the presentation, you can have a slide called "References", there you can list the paper in the reference style of your choosing (e.g. APA). This way it's very clear where the image comes from. 

I don't think the phrase "used with permissions" is necessary in a presentation. But I'm not certain. I'm sure others will comment on this. However, that phrase IS necessary if you were to publish the slides of your presentation, or if you will use that image in a paper.