Help

prezll is an image editing tool you can use right in your browser — no install, no sign-up required. Uploaded images are never sent to a server; everything is processed entirely in your browser.

1. Uploading an Image

Click the upload area in the center of the main screen, or drag and drop an image file directly onto it. JPEG, PNG, and WEBP formats are supported, and each file can be up to 10MB.

2. Cropping to the Ratio You Want

Select Crop from the tool list on the left to see ratio chips for platforms like Instagram, X, and Threads. Pick a ratio, or choose "Free" to draw a custom area by dragging, then resize it by dragging the corners.

3. Rotate · Flip

Each tap of 90° Rotate turns the image 90 degrees clockwise, and you can flip the image with Flip Horizontal / Flip Vertical.

4. Adjusting Color (Brightness · Contrast · Saturation)

Inside the Filter tool's Custom menu, three sliders let you control brightness, contrast, and saturation, each from -100 to 100. These stack on top of whichever filter you've picked, so you can fine-tune the exact tone you want. Below is an example with increased brightness, contrast, and saturation (left is the original, right is after adjusting).

Example with increased brightness, contrast, and saturation

5. Applying a Filter

The Filter tool lets you change the overall tone of the image by choosing from a wide range of presets. You can preview the exact effect that will be applied, then fine-tune it further with brightness, contrast, and saturation sliders in the Custom menu.

6. Covering Areas with Mosaic · Blur

Mosaic and Blur apply only to the area you choose, not the whole image. First, drag to select the area you want to cover (you can resize it using the corners), then adjust the strength with the slider that appears. With Mosaic, a higher strength shuffles pixels across a wider range at random. If you want to pick the area again, press "Reselect Area" to clear the existing effect and draw from scratch.

Mosaic covers an area by shuffling its pixels

7. Undo · Redo

If you make a mistake while editing, use the Undo / Redo buttons at the top to move between earlier and later states at any time.

8. Downloading

When you're done editing, press the Download button at the top to save at full original resolution. The filename is generated automatically in the format "Prezll+download time". Right-click is disabled on the editing screen to protect your image, and saving is only possible through the Download button.

9. Starting Over with a New Image

Press the prezll logo or the Remove Image button at the top left to clear your current work, return to the main screen, and upload a new image.

10. Editing a GIF

From the top right of the main screen (or the footer at the bottom of this page), press the GIF Edit link to go to a dedicated GIF screen, separate from the image editor. Once you upload a GIF file (up to 10MB), five tools become available.

Trim: Drag the start and end of the range to keep on the frame strip.
FPS: Setting a target FPS lower than the original reduces the frame count, which shrinks the file size too.
Crop: Just like the image editor, you can crop to Free/1:1/4:3/16:9/9:16 ratios.
Resize: Enter the width and height in pixels directly to reduce the resolution.
Compress: A higher compression strength reduces quality slightly but shrinks the file size further.

Press Confirm in each tool panel to apply the current setting, or Reset to revert just that setting to its original value. The top of the screen shows the original file size alongside the estimated size based on your current settings. When you're done editing, save your new GIF file with the Download button.