Which image to use as the base for a map? It depends. Here are the rules of thumb that I'm using.

If your map is going to be for a fancy purpose (i.e. science or a published product), begin with an orthorectified image from a Digital Terrain Model. (For more information about what's involved in the creation of Digital Terrain Models, read this explanation on the HiRISE website.) There are not very many of those and there's not much overlap between them, so it's usually obvious which one you need. I list those first. Those are mostly grayscale and were all acquired before landing.

If your map is going to be in an online article, a color image is usually a nice way to go. Since color swaths are only 1 kilometer wide, your choice of image will depend on which part of the traverse you want to show. I list the color swaths below in the order that Curiosity crossed them, and tell you which sols Curiosity was in them.

If you're writing about something that happened a while ago, odds are good that there is a HiRISE image that contains Curiosity parked near the place you're writing about. If not, there will, at least, be a photo containing the tracks Curiosity made at the time, though not necessarily in color. I indicate the sol of each photo that contains Curiosity hardware, and comment about which hardware/tracks are in color and which are in the grayscale portions of the swath.

A few things to keep in mind about HiRISE:

The HiRISE camera has 14 detectors, lined up on a large focal plane. Ten of the detectors see red wavelengths and form a staggered line that allow HiRISE to capture grayscale images 20,000 pixels across. At the middle of the focal plane are two more pairs of detectors that see blue-green and infrared light, allowing the HiRISE team to show the center 20% of any image swath in color.

If HiRISE is looking straight down or nearly so (emission angle near zero), it can achieve resolutions close to 25 centimeters per pixel. So a full swath is roughly 5 kilometers wide, and the color strip roughly 1 kilometer wide.

However, targeted images often require slews to one side or the other of the ground track, which decreases the resolution, but increases the swath width. When the emission angle isn't zero and there there is topography, there will be distortion caused by the oblique view. Map-projected image products correct for large-scale topography (like Gale crater's central mound) but not small-scale topography (like individual buttes and canyons). The only image products that are corrected for small-scale topography are the orthorectified images from digital terrain models.

No two images have quite the same lighting geometry. HiRISE operates on a nearly sun-synchronous orbit, so it always passes over spots on Mars in the afternoon. But if it slews to the east, it sees the ground at an earlier time of day, and if it slews to the west, it sees the ground at a later time of day. And Mars has seasons, so the directions and lengths of shadows are different on different days, even if taken at the same local time of day.

Digital Terrain Models over the Curiosity Field Site

Understanding the local topography and slopes at potential landing sites was crucially important to establishing the safety of a proposed landing site, so imaging necessary to create good-quality digital terrain models (DTMs) over potential landing sites was a high priority for Mars Reconnaissance Orbiter's prime mission long before Curiosity landed. DTMs are the preferred products to use for mapping the rover traverse because they have been orthorectified -- that is, the images have been corrected for geometric distortion caused by the shape of the landscape and HiRISE's oblique perspective onto it. Orthophotos from DTMs are as close to maps as photos get. However, it's true that images taken after landing that actually feature rover tracks (see below) make it much easier to map the rover's course; anybody who produces a map product relating to the Curiosity mission should use orthophotos as a base map but post-landing images to establish the precise location of the rover with respect to surface features.

First, a location map. The base image is a 10-meter-per-pixel Context Camera photo, colorized with a Mars Express HRSC image. The light yellow part of the path shows Curiosity's completed drive. The orange path should not be taken overly seriously -- it's a notional traverse developed in 2011 by Ryan Anderson, Dawn Sumner, and Jim Bell as they were trying to characterize what Curiosity might find in the field. It could represent where Curiosity will go, but it's not a "plan" as such and the future rover path will likely deviate from it at least a little and probably a lot. Also please note that the lat/lon lines drawn on here are intended as a guide but may not be perfectly precise -- I extrapolated them from a map covering a smaller area.