Thumbnail Generator
Create several thumbnail sizes from one image in a ZIP
Drop your file hereTap to choose a file
or click to browse, or paste from the clipboard
JPG, JPEG, PNG, WEBP, GIF
Max file size: 30 MiB
Size presets from one source
Choose 64, 128, 256, or 512 pixel bounds using the available presets, including a single 256-pixel option.
Proportional fit without enlargement
Each thumbnail fits within the selected square bounds while retaining the image proportions. A smaller source is not enlarged.
JPG or PNG files in a ZIP
Choose the image format and quality. All generated thumbnails are bundled into a ZIP, even when one size is selected.
How to Use Thumbnail Generator
- 1
Upload one supported image.
- 2
Choose the size preset, JPG or PNG, and quality.
- 3
Convert and download the ZIP, then extract and inspect the thumbnails.
What people use this tool for
- Create several image sizes for cards or product listings.
- Prepare preview assets while retaining the source aspect ratio.
- Generate small variants of an illustration for different layouts.
Frequently Asked Questions
Which input formats are accepted?
JPG, JPEG, PNG, WebP, and GIF. GIF input uses its first frame.
Are all thumbnails square?
No. Each size is a maximum bounding box, and the source aspect ratio is retained. Use Image Editor or Favicon Package if you need cropping to a square.
Does the tool create multiple images from multiple uploads?
It accepts one source image and generates selected sizes from that image. Batch Image Compressor provides a separate workflow for multiple image files.
What happens to transparency and quality?
PNG can keep existing alpha transparency, but its quality setting can change colors through palette encoding. JPG fills transparent areas with white and uses lossy encoding.
What is the upload limit?
The default limit is 30 MiB for one file. Check the upload area for the current limit. The server upload ceiling is 100 MiB per file; file complexity and processing time can also limit conversion.
Where are files processed and when are they removed?
This tool uploads files to Zutilium's server for processing. After a successful conversion, uploads are scheduled for deletion after about one minute and generated downloads after about ten minutes. Cleanup runs periodically, so removal is not immediate. Save your result promptly.