From the web or an iOS device, click or tap the "compose new Tweet" button . From an Android device, tap on "What’s happening? "
From the web, click "Add photo". From a device, tap the camera icon to take a photo, or choose a photo from your gallery.
Once a photo is selected, you will see a thumbnail image (or file name) appear as an attachment. You can select up to 4 images to tweet at once. (Note: Animated GIFs cannot be included in Tweets with multiple images.)