A photo mosaic is a large image composed of many smaller images (called tiles). When viewed from a distance, the tiles blend together to form a recognizable larger picture. Up close, you can see the individual tile images. This technique is widely used in art, advertising, and digital design to create visually striking compositions.

The tool divides your main image into a grid. For each grid cell, it calculates the average RGB color. Then it searches through your tile library (preset colors + uploaded images) to find the tile whose average color is closest using Euclidean distance in RGB space. The best-matching tile is placed in that cell, creating the mosaic effect.

No. Everything happens locally in your browser. Your images are never uploaded to any server. The tool uses the HTML5 Canvas API and JavaScript to process all images directly on your device. This ensures complete privacy and also makes the tool faster since no network transfer is needed.

For best results, we recommend 20-100 tile images with diverse colors and tones. The tool comes with 35 preset color tiles, so you can start immediately. Adding your own images (photos, textures, patterns) greatly enriches the mosaic. Even 10-20 well-chosen tile images can produce excellent results when combined with the preset colors.

The tool supports all common image formats including JPEG, PNG, WebP, BMP, and GIF (static frames only). The output mosaic is always generated as a PNG file for maximum quality. For tile images, both photos and graphic designs work well.

For optimal results: (1) Use a main image with good contrast and recognizable features. (2) Set columns between 25-40 for a balance of detail and performance. (3) Use an overlay opacity of 25-35% to help the original image shine through. (4) Upload diverse tile images covering a wide color gamut. (5) Avoid extremely dark or washed-out main images as they produce less defined mosaics.

Yes! The tool is fully responsive and works on smartphones and tablets. On mobile devices, you can upload images from your photo library or take a photo directly with your camera. The interface adapts to smaller screens for comfortable use. For very large mosaics on mobile, generation may take slightly longer due to hardware limitations.

Overlay opacity controls how much of the original main image is blended on top of the mosaic. At 0%, you see a pure mosaic made entirely of tiles. At higher percentages (20-40%), the original image is semi-transparently overlaid, which helps the overall picture remain more recognizable while still showing the tile details underneath. Most users find 25-35% produces the most pleasing balance.

Yes. Hover over any uploaded tile thumbnail and click the red "X" button to remove it. You can also click "Clear Uploaded" to remove all custom tiles at once. The 35 preset color tiles are always available and cannot be removed, ensuring the tool always has a fallback tile library.

Absolutely! The Photo Mosaic Creator is completely free with no registration required. There are no watermarks on downloaded images, no usage limits, and no hidden fees. Generate as many mosaics as you like and download them in high quality.