I agree we should tread carefully regarding feature creep, but it's already very common to display graphical data in the terminal with ASCII art or Unicode. Adding basic bitmaps would remove the need for those hacks.
Convenient terminal tools already exist for viewing formatted text like Markdown or HTML, or viewing binary data like ELF files, or showing live dashboards like htop... but images still require launching a separate application. And this is all data that you might produce while working solely within the terminal--only to have to visit GUI land to see what's in a PNG file. It's a pretty obvious gap.
Convenient terminal tools already exist for viewing formatted text like Markdown or HTML, or viewing binary data like ELF files, or showing live dashboards like htop... but images still require launching a separate application. And this is all data that you might produce while working solely within the terminal--only to have to visit GUI land to see what's in a PNG file. It's a pretty obvious gap.