Reader RushFanForever dug up this interview from back in late 2012 with Canadian photographer Deborah Samuel. Samuel worked with Hugh Syme on some of Rush's most iconic album covers, namely Permanent Waves, Moving Pictures, Exit Stage Left and Signals. Here she discusses her role in photographing the Permanent Waves cover:

... Hugh Syme ... hired me to style the ... cover because of my work in music and fashion. There were already 2 photographers ... who had supplied the background hurricane shot and band shots. I ended up styling the model and shooting the newspaper (Dewey defeats Truman) while another British photographer, Fin Costello shot the Permanent Waves girl and Hugh Syme leaning against the pole waving on the cover. We then took the 4 elements-background hurricane shot by Flip Shulke, Permanent Waves girl, newspaper and Hugh leaning against the pole and printed the 4 negatives onto 1 piece of paper...a feat done before the invention of Photoshop ... took all night to get one image where the register of the 4 images onto 1 piece of paper was achieved.
The work we did on Permanent Waves led Hugh and I to doing numerous album covers together. ...

The model referred to was of course Paula Turnbull, but you may not have known that the man leaning against the pole was Hugh Syme himself. Which brings us to the Moving Pictures cover:

... Seeing as Hugh had put himself on the Permanent Waves cover it was my turn to be on the Moving Pictures cover as Joan of Arc, in one of the 3 paintings that were being moved by the moving men... In being Joan of Arc, I dressed in burlap, stood with my back to a pole with a shutter release cable in my hand, in order to take the picture, while Hugh squirted lighter fluid into a pie plate that was just in front of the lens and tossed in a match. ...

One of moving men was Mike Dixon, and you can see a video interview with him in this post. And then came Exit ... Stage Left, which was extremely difficult to put together as Deborah describes here:

... Paula Turnbull (the Permanent Waves girl) was living in Paris and a top model there. We had to bring her to Toronto from Paris for 1 night to shoot this cover. ... I contacted the vintage clothing store where I had rented [her costume] before and they still had the original sweater and the skirt in their inventory, which was a miracle really. The man who had played the King on The Farewell to Kings covers lived in Alberta and had to be found, and brought to Toronto. He got off the plane the night of the shoot and became very ill meaning we had to find a replacement for the King character within a couple of hours as we ... only had 6 hours to get the shot done. Hugh went out on Yonge Street looking for anyone that resembled the original King character. He found a young man on Yonge Street, who agreed to be the King. In he came ... got dressed up in a King costume and took on the role of the King in the middle of all this mayhem. I often wondered what was going through his mind during the shoot. It had to have been especially bizarre for him to walk into this production at the last moment. ...

Deborah also worked on the relatively simple concept for the Signals album. You can check out the entire, very interesting interview with Deborah at this location.