Works fine for me.
I open a conversation, click the Paper Clip icon at top of the screen, select Gallery from the dropdown choices which appear, select an image, click Send.
I just successfully sent my wife am image using that procedure. Just curious: what happens if you go directly to the Gallery, select an image, tap the Share icon, and then tap WhatsApp? Does it work if you do it that way?
What version of WhatsApp are you running? Open WhatsApp, tap the menu icon at top right of screen, tap Settings, tap About. I am on Version 2.11.152.