Alec! Thanks for the response. That’s why I added this to the article:
EDIT 02–14–19: There is a way to enable quickly changing between color mode and grayscale. This is convenient for when you want a color screen to view a photo, but don’t want to leave it on all the time. To enable this:
Navigate to General > Accessibility
Find Accessibility Shortcut at the bottom of the screen
Open it, set it to Color Filters
At the top of the menu selection, it will say something like “triple click the side button for:” On an iPhone X, it says the side button. On older iPhones, it may say the home button.
That’s it! Now you can triple click the side button (or whatever your shortcut is) to quickly switch between color and grayscale mode.
I am able to turn on color for things like this when necessary, which isn’t too terribly often — especially now that full color makes me a little sick with the oversaturation.