These images are created as a fall back for if the normal kernel doesn’t boot.
initramfs-linux-fallback.img
initramfs-linux-lts-fallback.img
These ones are the normal images for booting.
initramfs-linux.img
initramfs-linux.img
And the kernels.
vmlinuz-linux
vmlinuz-linux-lts
Many people just install the lts kernel in case they have a problem with the normal kernel, as a backup. See this topic.