Dummy Image Generator Online
Generate dummy images of any file size instantly in your browser. BMP for exact size, JPEG for approximate. Free, no upload, no server — perfect for testing file upload limits.
Frequently Asked Questions about Dummy Image Generator
How do I generate a dummy image of a specific file size?
Enter your desired file size in MB, select BMP for an exact size or JPEG for an approximate size, then click Generate. The image is created entirely in your browser and downloaded immediately — no server involved.
What is the difference between BMP and JPEG output?
BMP (Bitmap) is an uncompressed format, so the file size is exact and predictable. JPEG uses a calibration step to measure the actual bytes/pixel ratio in your browser, achieving within ±5% accuracy. Use BMP when exact size is critical.
Why do developers need dummy image files?
Dummy images are used to test file upload size limits on servers and APIs, simulate network load with large files, stress-test image processing pipelines, and verify that file size validation logic works correctly.
What is the maximum file size I can generate?
There is no hard limit enforced by the tool, but your browser's memory sets the practical limit. Files up to 200MB typically work fine on most modern devices. Very large files (500MB+) may cause slowness or browser crashes depending on available RAM.
Is the generated image a real viewable image?
Yes. BMP files contain valid image data filled with random noise and can be opened in any image viewer. JPEG files are also valid and viewable. Both formats pass standard file type validation checks.
Is this tool free and private?
Yes, completely free. All image generation happens 100% inside your browser using the Canvas API. No files are uploaded to any server. Your data and generated files stay entirely on your device.
Can I use the generated files to test API file upload limits?
Yes, that is one of the primary use cases. Generate a file just above your server's upload limit (e.g., 10.1MB for a 10MB limit) to verify your validation logic correctly rejects oversized uploads.