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AI Image Generator for Social Media: How to Use One Well

By PostMediaAI7 min read

An AI image generator creates a picture from a text description, which you can use as the visual for a social media post. It is useful for concept images, backgrounds, illustrations, seasonal graphics and quote cards, especially when you do not have a designer or a fitting photo. It is a poor substitute for real photos of your actual product, team or location, and realistic AI images of people or events may need a label on some platforms.

The short version: describe the subject, style, composition and format in your prompt, generate a few options, edit the best one for size and text, check the platform’s AI labeling rules, then schedule it with your caption.

When AI images work well on social media

  • Illustrations and concept art for tips, explainers and announcements.
  • Backgrounds for quote cards, carousels and text-led graphics.
  • Seasonal or themed visuals, such as an autumn-styled header for a newsletter post.
  • Mood images for ideas that are hard to photograph, such as "a calm Monday morning".
  • Variations of a visual style you want to keep consistent across a series.

When to use a real photo instead

  • Your actual product, food, shop, team or work. Customers expect to see the real thing.
  • Before-and-after results. An AI image here would mislead people.
  • Events that happened. Use photos from the event.
  • Anything where a realistic image could be mistaken for a real person or situation.

How to write a good image prompt

Most image generators respond well to prompts with five parts:

  1. Subject: what is in the image, specifically. "A ceramic coffee cup on a wooden counter" beats "coffee".
  2. Style: photo, flat illustration, watercolor, 3D render, line art.
  3. Composition: close-up or wide, centered or off-center, empty space on one side for text.
  4. Mood and color: warm morning light, muted pastels, your brand colors.
  5. Format: square, vertical 4:5 or 9:16, or landscape, depending on where it will be posted.

Example: "Flat illustration of a small bakery counter with loaves on shelves, warm orange and cream colors, empty space on the left for a headline, vertical 4:5 format, no text in the image."

Ask the generator to leave text out and add your own text in an editor. Generated lettering is often misspelled.

Sizing AI images for each platform

Generate in the shape you need, or crop afterwards. Some official recommendations:

  • Instagram feed: aspect ratios between 1.91:1 and 4:5, shared at up to 1,080 pixels wide (Instagram Help).
  • Pinterest: a 2:3 ratio such as 1,000 by 1,500 pixels is recommended for image Pins (Pinterest Create).
  • LinkedIn: photos at least 1,080 pixels wide are recommended, with ratios from 3:1 to 4:5 (LinkedIn Help).
  • YouTube thumbnails: a 16:9 ratio for videos (YouTube Help).

For a full list, see our guide to social media image sizes.

Editing AI images before posting

  1. Crop to the right ratio for each platform.
  2. Add your headline, logo or text in an editor rather than in the prompt.
  3. Check details: hands, faces, text, product shapes and anything odd in the background.
  4. Adjust colors to match your brand.
  5. Export at the platform’s recommended size.

AI labels and disclosure rules

Major platforms ask creators to disclose realistic AI-generated content:

  • Meta says it requires people to use its AI disclosure tool when posting photorealistic video or realistic-sounding audio that was digitally created or altered, and it labels content it detects as AI-generated (Meta).
  • TikTok requires creators to label AI-generated content that contains realistic images, audio or video (TikTok Support).
  • YouTube requires creators to disclose realistic altered or synthetic content when they upload (YouTube Help).

Clearly stylized illustrations are usually treated differently from realistic images, but the rules change, so check each platform’s current policy. When in doubt, label it.

Copyright and rights

Image generators have different terms about how you can use their output. Read the terms of the tool you use, avoid prompts that copy a living artist’s style or a brand’s characters, and do not generate images of real people without their permission.

A simple workflow for AI visuals

  1. Write the caption first so the image supports a clear message.
  2. Generate three or four image options in the right format.
  3. Choose one, edit it and add any text.
  4. Check the platform’s labeling rules.
  5. Attach it to the post and schedule.

Our guide to AI social media content creation covers the caption side of this workflow.

Creating images in PostMediaAI

PostMediaAI includes AI image generation and the Advanced Picture Editor, so you can generate a visual, polish it and attach it to the post without switching tools (PostMediaAI features). Images go into a shared media library for reuse, and the post publishes to the channels you choose across 30+ channels. Every plan includes the Advanced Picture Editor (pricing); check the pricing page for what else each plan includes.

FAQ

Is there a free AI image generator for social media posts?

Several AI image tools have free tiers with limits on how many images you can create or on image quality. Check the usage rights in their terms before using images in business posts.

What is the best AI image generator for social media?

It depends on the style you need and where you work. A generator built into your scheduling tool saves time if you want to generate, edit and post in one place. A standalone tool may offer more styles.

Do I need to label AI images on Instagram and TikTok?

TikTok requires labels on realistic AI-generated content, and Meta requires disclosure for photorealistic video and realistic audio that was created or altered and labels content it detects as AI-generated. Check each platform’s current rules before posting.

Can I use AI images for my business?

Many businesses do. Check the generator’s terms for commercial use, avoid realistic images that could mislead customers, and use real photos for your actual products and results.

Related guides: AI Social Media Post Generator: One Idea, Every Channel, AI Video Generator for Social Media: Short Videos Guide and How to Write Social Media Posts People Actually Read.

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