Open Instagram and tap Your Story or the camera icon
Select the first photo from your gallery
Tap the sticker icon
Choose the photo sticker or gallery sticker
Add another picture from your gallery
Resize, move, and rotate the picture as needed
Repeat to add more pictures
Tap Your Story to post it
Use the layout tool before posting if you want multiple pictures in separate frames
Use copy and paste from your camera roll if your device supports it
Use third-party collage apps if you want more layout options