For the heck of it, I browsed through all the backgrounds in REmaster. It's an interesting way to see how they've handled each scene. There's not really anything new to learn, it's basically confirming what Capcom has said they've done with the game, and stuff you can observe by playing it.
It's obvious they've spent a extra lot of special time with all the outdoor areas, as they look super weird when looking at just the static background image. For instance, here's a bunch:
http://abload.de/img/r20304_000_bm_nomiptrkc4.png
http://abload.de/img/r31112_000_bm_nomip3vj6w.png
http://abload.de/img/r31111_000_bm_nomipi2jim.png
http://abload.de/img/r31109_000_bm_nomip7ejf6.png
http://abload.de/img/r31110_000_bm_nomipqgkp4.png
http://abload.de/img/r31107_000_bm_nomip3uk1c.png
http://abload.de/img/r31105_000_bm_nomipwvj9c.png
http://abload.de/img/r31106_000_bm_nomip8ujug.png
http://abload.de/img/r31104_000_bm_nomip5pj3c.png
http://abload.de/img/r31101_000_bm_nomip66jfb.png
http://abload.de/img/r31108_000_bm_nomipafk7u.png
http://abload.de/img/r311_bgz-00000000013ejs9.png (REmake version. most of the forest are rendered using movie files in REmake version, but this is one of the few exceptions)
And the "I just don't give a shit" award goes to this background:
http://abload.de/img/r20607_000_bm_nomipjwk7r.png
That's one of the backgrounds used in the cutscene where you save Rebecca from a hunter. Looks like they applied something similar to a nearest neighbour filter and called it a day.
In a few areas, they are rendering the background essentially as a "movie file." For instance, there's one room in the residence with some really subtle water effects on the ground, and while there's only 2 angles in the room, there's 60 different pictures. So it's cycling through the images one frame at a time. Same thing with many rooms in the the entire laboratory. Once the alarm is on, there's red light animating which is done by cycling through background images. Giant fan is animated the same way.
All in all, there's 2500 unique background images in REmaster. Far more than REmake as that uses literal movie files for many of the rooms.
If it was just the Gamecube assets with no changes then that would be really weird, but this is on a new engine with all assets at a much higher quality. And as far as I know, all those frame drops are related to camera switches. The game probably loads in each background as they're used, and I guess loading more than 10mb worth of texture data in the time span of 33ms ends up being a bit tricky.
On the bright side, this should not be very noticeable while playing the game. When I played through 360 version, I had to look at captured footage to realize it was dropping frames for each camera switch.