The best aspect ratio for an AI image depends on where it will be posted. Use 4:5 for Instagram feed posts, 9:16 for Stories, Reels, TikTok and YouTube Shorts, 16:9 for YouTube thumbnails and standard video, and 1:1 for product listings and profile pictures. The most reliable approach is to pick the ratio before you generate, because AI models compose the scene for the frame they are given rather than cropping a finished picture well.
As of 30 October 2026, the ratio you choose also limits which models and sizes you can use. Each Kenerate model offers its own list, so the same ratio may not be available everywhere.
What is an aspect ratio?
An aspect ratio is the width-to-height relationship of an image or video. A 9:16 frame is tall and narrow, like a phone held upright. A 16:9 frame is wide, like a TV or a YouTube video. A 1:1 frame is square. Two images can have the same number of pixels and still crop very differently once they are placed in a feed, so the ratio decides how much of the scene a viewer sees.
Which aspect ratio should I use for each platform?
| Where it will be posted | Recommended ratio | Common pixel size | Notes |
|---|---|---|---|
| Instagram feed (photo) | 4:5 | 1080 x 1350 | Takes the most vertical space in the feed |
| Instagram Reels and Stories | 9:16 | 1080 x 1920 | Full-screen vertical |
| TikTok | 9:16 | 1080 x 1920 | 16:9 is also accepted |
| YouTube Shorts | 9:16 | 1080 x 1920 | Same as other vertical video |
| YouTube video and thumbnail | 16:9 | 1920 x 1080 | Standard landscape |
| Facebook feed | 16:9 or 1:1 | Varies | Both show well in the feed |
| X (Twitter) | 16:9 | 1280 x 720 | Other ratios get cropped in the timeline |
| Product listing or marketplace | 1:1 | Varies | Square keeps the product centred |
| Pinterest pin | 2:3 | Varies | Tall pins win the grid |
Sources disagree on exact pixel sizes, and platforms change their specifications. Check each platform's help centre before you export a final file. The ratios in the table are the ones most guides agree on in 2026.
Why does the same image look different in a feed?
Feeds crop images to fit a fixed frame. A 4:5 photo in a 1:1 slot loses some of its top and bottom. A 16:9 landscape image shown in a 9:16 Story loses most of its sides, which is where faces and text often sit. The safe habit is to keep the subject in the centre third of the frame and leave margins for text.
Taller frames give a subject more screen space in a vertical feed. Wide frames suit banners, hero images and cinematic scenes. When you generate in the wrong shape and then crop, the subject often gets cut off, and the result looks worse than an image generated at the correct ratio from the start.
Can I just crop a 1:1 image to 9:16?
You can, but the result is usually weak. Cropping a square to a 9:16 frame keeps only about 56 percent of the width, so most of the scene is discarded. Faces get cut and the composition breaks.
A better workflow is to generate at the target ratio. If you need several formats from one idea, generate one image per ratio with the same prompt, then review each one. This costs more generations, but each output is composed for its own frame.
Which aspect ratios does Kenerate offer?
The ratio list depends on the model. These are the lists in Kenerate's model configuration as of 30 October 2026:
| Model family | Image ratios offered | Video ratios offered |
|---|---|---|
| Seedream (image) | Presets including 1:1, 3:4, 2:3, 9:16, 4:5, 5:4, 4:3 and 3:2 | n/a |
| Qwen Image | 15 ratios, including 1:2, 2:1, 9:16 and the 21:9 cinema frame | n/a |
| Seedance 2.5 (video) | n/a | 16:9, 9:16, 4:3, 3:4, 1:1, 21:9 |
| Wan 3.0 (video) | n/a | 16:9, 9:16, 1:1, 4:3, 3:4 |
| Veo 3.1 (video) | n/a | 16:9, 9:16 |
Video models with fewer ratios, such as Veo, are best for 16:9 and 9:16 content. If you need a square video, pick a model that lists 1:1, such as Wan 3.0 or Seedance 2.5.
How do I choose a ratio step by step?
- Decide the placement first. Write down the exact place the file will appear, such as "Instagram feed", "Reels" or "YouTube thumbnail".
- Match the ratio to the placement. Use the table above. If the placement is unclear, use 4:5 for still images and 9:16 for video, which covers most social feeds.
- Check the model supports it. Open the ratio picker for the model you plan to use and confirm your ratio is listed. If it is not, switch models rather than cropping.
- Write the composition into the prompt. Say where the subject sits, for example "subject centred, empty space at the top for a caption" or "wide shot with the character on the left third".
- Generate, then review the crop. Look at the image at phone size before you post it. Check that faces and text are not near the edges.
- Export at the platform size. Upscale only if the platform needs a higher pixel count. Upscaling a small image does not add detail.
Does the aspect ratio change the cost?
Prices depend on the model, resolution and duration, not on the ratio alone. Video is billed per second, so the length of the clip matters more than its shape. Read AI video cost per second in 2026 for the current rates by model. The pricing page lists the credit packs.
How do aspect ratios work for AI video?
Video adds a second question: will the frame still work once the camera moves? A 9:16 clip keeps the subject tall and close, which suits talking-head and product shots. A 16:9 clip suits establishing shots and wide action. If you plan to animate a still image, make the still at the final ratio first, then use it as the start frame. The image to video AI page explains this workflow, and the vertical AI video guide for Reels and TikTok covers framing for vertical clips in more detail.
What about product photos and ads?
Product images usually need two sizes: a square for listings and a 4:5 or 9:16 version for social ads. Generate the main product shot at 1:1 for the catalogue, then build the vertical ad from its own prompt so the product stays in the safe zone. If you need a dedicated workflow for ads, the AI product video generator page shows the steps.
Common mistakes with AI image ratios
- Cropping the subject out. Full-body shots become headshots when the frame is too narrow. Describe the framing in the prompt.
- Putting text at the edges. Feeds and Stories cover the top and bottom with interface elements. Keep text away from the outer 10 percent.
- Using one ratio for everything. A single 1:1 image rarely fits every placement. Plan two or three ratios from the start.
- Assuming all models behave the same. Model support for each ratio differs. Check the list before you build a campaign around one model.
- Ignoring the pixel count. A 1:1 image at 512 pixels is too small for a 1080 wide feed. Generate at a higher size or upscale before you post.
Where do I start?
If you only post on one platform, start with that platform's ratio and keep it. If you post everywhere, make one 4:5 image for feeds and one 9:16 version for Stories and Reels, then add a 16:9 version only for YouTube or X. You can generate these in the AI image generator. Reuse one prompt with a different ratio to keep the look consistent across placements, and keep a note of which ratio each file was made for so the feed version is never reused as a Story. A small set of matched files, one per placement, usually does more for a campaign than one image stretched across every format.
Sources
- Kapwing: Social media video aspect ratios and sizes guide — platform ratios for YouTube, Reels, TikTok, Facebook and X. The page is titled as a 2025 guide.
- PromptSpace: AI image aspect ratios for every platform — how ratio changes AI image composition, and the advice to generate at the target ratio instead of cropping.
Platform specifications change. This guide was checked as of 30 October 2026 and will be updated when platforms change their recommended sizes.
Updated 30 October 2026.
