Do you want to reply to a message with a meme or a GIF that you've seen that one time? Need photos of Eyjafjallajökull? Yeah, you can open a browser and search it by the image. Then save it, then open a dialogue, then send it and then...what a waste of time, isn't it? And then deleting this image. Isn't there a faster way?
There is. One of the "hidden" Telegram features is searching images and GIFs as simple as attaching a picture. You'd only have to tap the search icon in the upper menu and type in what you're looking for in the search field.
How to: open dialogue -> attach a file (the icon is in the lower left corner) -> Photo or Video -> Search (the icon is in the upper right corner) and then you send the right file