These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.03 s (backtrack: 0/20).

[ebuild  N     ] x11-libs/xcb-util-0.4.1::gentoo  262 KiB
[ebuild  N     ] x11-libs/xcb-util-image-0.4.1::gentoo  283 KiB
[ebuild  N     ] x11-misc/xwallpaper-0.7.6::gentoo  USE="jpeg png seccomp -xpm" 88 KiB

Total: 3 packages (3 new), Size of downloads: 631 KiB