An AI image aspect ratio changer takes a picture in one shape and returns it in another, such as a square post as a 9:16 Story or a portrait photo as a 16:9 banner. In Toybox AI, Smart Editor does the job: upload one photo, choose a new Shape, and type what should change. It redraws the whole picture in the new shape, so the result is a new image based on yours rather than your original with strips added to the sides. Below are the jobs it suits, the exact output sizes, instructions you can copy, and when a true extend tool is the better choice.
What you can make with an AI aspect ratio change
Each of these starts from one photo in Smart Editor, which offers four fixed shapes plus Original.
A square post as a 9:16 Story
Instagram Stories fill an upright phone screen at 9:16. Choose Story, and at 4K the result is 2160 x 3840 pixels. Ask for the extra height to go to plain background, like sky or a tabletop, so there's room for text away from the top and bottom edges. The safe margins, worked out in pixels, are on the Instagram post and Story size page.
A portrait photo as a YouTube banner
YouTube asks for channel banners of at least 2048 x 1152 pixels at 16:9, recommends 2560 x 1440, and keeps text and logos safe inside a center area of 1235 x 338 pixels at the minimum size. Smart Editor's 4K Wide setting returns 3840 x 2160, above the recommended size; HD Wide is 1824 x 1024, below the minimum. YouTube's file limit is 6 MB, and a 4K PNG of a detailed photo can go over it, so check the file size and save a JPG copy if it's too big. For a banner designed from scratch, see the YouTube banner guide.
A landscape photo as a 4:5 feed post
Choose Social 4:5 to turn a wide vacation or product shot into a portrait post. At 4K it's 2560 x 3200 pixels. The new shape is much taller than the photo, so say what belongs above and below the subject, such as more of the floor or the sky.
A flyer as a Story
Flyer Maker makes flyers in Portrait 4:5, Tall 3:4 and Wide 5:4, with no 9:16 size. Open a finished flyer in Smart Editor and pick Story to get a 9:16 version. The text is redrawn along with everything else, so read every date, time and price again before you post.
A square profile or listing thumbnail
Square 1:1 is 2880 x 2880 pixels at 4K and 1024 x 1024 in HD. It suits a profile photo or a product shot for a marketplace grid, where the subject needs to sit in the middle with even space around it.
A new picture in the shape you need
If you have no photo to start from, use an AI image generator with an aspect ratio setting. Image Generator makes a picture from a description in Square 1:1, Portrait 3:4, Landscape 4:3, Story 9:16 or Wide 16:9. It also takes up to 3 reference photos to guide the style, subject or layout, though faces can come out different from the originals.
Crop, extend or redraw: three ways to change a shape
There are three ways to get a photo into a new shape, and they treat your original very differently:
| Method | What happens to your photo | Where to do it | Pick it when |
|---|---|---|---|
| Crop | Edges are cut away to fit the shape | Crop in iPhone Photos (presets such as Square, 9:16 and 5:7) or Aspect ratio in Google Photos | The subject has room around it and losing the edges is fine |
| Extend (outpainting) | The original stays; new scenery is generated past the edges | Extend in iPhone Photos, Generative Expand in Photoshop, Auto frame in Google Photos (which can also recompose) | The original pixels must stay exactly as shot |
| Redraw | The whole picture is generated again in the new shape | Smart Editor | You want other changes too, or a crop would cut off the subject |
Extend in the iPhone Photos app needs Apple Intelligence on iOS 27 or later, on an iPhone 15 Pro, iPhone 15 Pro Max or iPhone 16 model or later. Open the photo's editor, tap Tools, then Extend, pinch or drag the picture to grow the background, and tap Extend. In Photoshop, drag the Crop tool's handles outward past the canvas, select Generative Expand, and leave the prompt blank to let it continue the scene. In Google Photos, Auto frame sits in the Crop tools and uses AI to fill in or expand the picture. The difference between filling inside a photo and adding outside it is explained in what inpainting and outpainting are.
Output sizes for each shape
The Quality setting fixes the pixel size, whatever size your upload was:
| Shape in Smart Editor | HD | 4K | Common use |
|---|---|---|---|
| Original ("Keep as is", a 4:3 photo) | 1360 x 1024 | 3312 x 2480 | Editing without reshaping |
| Square 1:1 | 1024 x 1024 | 2880 x 2880 | Profile photos, square posts |
| Social 4:5 | 1024 x 1280 | 2560 x 3200 | Instagram feed posts |
| Story 9:16 | 1024 x 1824 | 2160 x 3840 | Stories, phone wallpapers |
| Wide 16:9 | 1824 x 1024 | 3840 x 2160 | YouTube banners, slides, desktop wallpapers |
4K tops out at about 8.3 megapixels, so a 12-megapixel upload returns at roughly 8 megapixels. That's plenty for social posts and screens. For a large print, see upscaling a photo for large prints, which enlarges your original instead of redrawing it.
Tips for better reshaped images
- Say what fills the new space. The AI chooses how to fit the scene unless you tell it: more sky, more wall, more of the table.
- Name what must not change. Faces, product labels and logos can drift in a redraw. List them in the instruction.
- Pick the nearest shape. Going from square to Social 4:5 needs a quarter more height. Square to Story 9:16 needs about three quarters more, so expect bigger changes.
- Reshape before you add text. Put the headline on after the shape is final, so it isn't redrawn with the rest.
- Keep banner subjects in the middle. YouTube warns that banners are cropped on some devices and views, and only its center safe area is meant for text and logos.
Instructions you can paste into "What should change?":
Change this to a tall vertical format. Keep the couple, their faces and their clothes exactly as they are, and fill the extra space above them with more of the evening sky and the tops of the pine trees.Make this a wide 16:9 banner. Keep the bakery counter and the cakes in the center, and continue the white tile wall and the wooden shelves out to both sides. Don't add any text or people.Turn this into a 4:5 portrait post. Keep the ceramic vase, its shape and its label unchanged, and add more of the linen tablecloth below it and more of the plain cream wall above it.Reshape this flyer to a tall 9:16 Story. Keep every word, date, time and price exactly as written, keep the colors, and center the text block so the top and bottom edges stay clear.Limits to know
- It may not extend the scene. Smart Editor doesn't crop your photo or add blank canvas, but it also doesn't promise to keep your original and build outward. It may zoom in, show more at the edges or rearrange things. Describe the new area in the instruction, and if the original must stay pixel-for-pixel, use Extend or Generative Expand instead.
- Other parts of the picture can move. There's no brush or mask, so each edit redraws everything. Say "keep everything else the same", then switch "Editing" to "Original photo" and try again if something important moved.
- Only four new shapes. Smart Editor offers Square 1:1, Story 9:16, Wide 16:9 and Social 4:5. For 3:4, 2:3 or 21:9, crop a result afterward, or use Image Generator Lite, which has 14 shapes and takes up to 3 photos for light edits, always at 1K.
- One photo per edit. Smart Editor can't combine two photos into one wide frame. Image Generator's reference photos are the route for that.
- Pro plan required. Smart Editor currently costs 85 credits in HD and 110 in 4K. See current prices.
AI image aspect ratio changer vs resizer vs converter
These names get used for three separate jobs. An aspect ratio changer alters the shape, such as 1:1 to 9:16. A resizer or size changer keeps the shape and changes the pixel count, such as 1080 x 1080 to 2160 x 2160. An AI image size expander makes the canvas bigger by adding picture around the original, which is what the extend tools above do. A tool called an image size converter may resize, change the file type (such as HEIC to JPG), or both, so check which one it does.
Smart Editor does the first job and part of the second: Shape sets the new shape, Quality sets the pixel count, and the result downloads as a PNG. If you only need a bigger file in the same shape, an upscaler keeps closer to your original. If you only need a different file type, use your photo app's export or save-as option.
How to change an image's aspect ratio in Smart Editor
- Go to Smart Editor and log in. Your account needs a Pro plan or higher.
- Under "Your image", upload one JPG or PNG up to 10 MB.
- In "What should change?", say what should fill the new space and what must stay the same.
- Open "More options". Under "Shape", pick Square, Story, Wide or Social. Under "Quality", pick HD or 4K.
- Tap "Apply edit". Most image tools finish in about 30 seconds.
- Check the edges, faces and any text at full size. To adjust, type the next change and apply it to "Latest result", or switch to "Original photo" to start from your upload again.
- Download the PNG, or save it to your gallery. Unsaved results stay available for 24 hours.