Know the common ratios
A 1:1 ratio is square and often suits avatars, product tiles and profile artwork. A 16:9 ratio is a wide landscape format used for many video thumbnails, presentations and hero banners. A 9:16 ratio is tall and often suits vertical short-form video. A 4:3 ratio is less wide and can work for slide-like images or traditional photo layouts.
Ratios describe shape, not quality or resolution. A 16:9 file can be small or large in pixel dimensions. If a platform sets exact pixel requirements, meet those requirements separately and preview the upload.
| Ratio | Shape | Typical use |
|---|---|---|
| 1:1 | Square | Avatars, cards, product tiles |
| 16:9 | Wide | Video thumbnails, banners |
| 9:16 | Vertical | Short-form video, stories |
| 4:3 | Classic landscape | Slides, document visuals |
Plan composition for the frame
Before generating an image, decide where the main subject will sit. If the image needs text on the left, ask for negative space on the left and place the subject to the right. If a vertical crop is required, keep the face or key object away from the edges where a platform might crop it.
Think about what must survive a crop. A full-body character can fit comfortably in a vertical frame but may become tiny in a square crop. A wide landscape can create an expansive mood, but the main object may be lost when shown as a small card. Match composition to the actual viewing size.
Write a more complete image prompt
A useful prompt describes the subject, setting, style, composition, lighting and output shape. For example: “A friendly study robot beside a stack of books, clean light-blue studio background, soft daylight, subject on the left, open space on the right for a heading, polished 3D illustration, wide 16:9 frame.” This gives the generator more direction than simply requesting “a robot”.
Add constraints only when they matter. If you need a realistic photo, do not mix it with conflicting instructions such as “flat vector icon”. If you need a clean background for an overlay, say so explicitly and check the result before use.
Generate, inspect and iterate
After receiving an image, check whether the primary subject is recognisable at small sizes, whether the background competes with the subject and whether any requested empty space is actually available. Generated text can be misspelled or distorted, so create headings with HTML or an image editor when accurate text matters.
If the composition is close but not right, adjust one variable per revision: move the subject, simplify the background, change lighting or request more negative space. When you change the ratio, recheck the composition instead of assuming the generator will preserve every detail.
Think about rights, privacy and consistency
Avoid adding a real person’s private information or an unapproved likeness into a prompt. If you use a brand logo or a protected character, make sure you have the rights and that the use is appropriate. Check the image generator’s current terms for commercial-use conditions and restrictions.
For a coherent website, establish a small style system: a defined colour palette, lighting direction, icon style and range of ratios. A consistent set of images helps users recognise the brand even when each tool has a different subject.
A fast pre-generation checklist
Choose the target platform first. Select a ratio that fits its display. Describe the focal subject and where it belongs in the frame. Reserve negative space for text when needed. Name the visual style and lighting. After generation, inspect small-size readability, unexpected text, edge crops and background clutter.
If the image will appear beside an article, write useful alt text that explains its purpose to people who cannot see it. Do not stuff alt text with keywords or repeat nearby headings verbatim.