Image Overlay
Composite two images with 16 blend modes, opacity, scale, and position. Watermarks, logo placements, double-exposure effects, and visual diffs. Runs in your browser.
Drop the base image (background)
Step 1 of 2 — never uploaded
How image overlay works
ToolChop draws the base image onto a canvas at native resolution, then draws the overlay on top with one of 16 W3C-standard blend modes (Multiply, Screen, Overlay, Hue, etc.) and a chosen opacity. Scale and X/Y offset position the overlay precisely. The result is exported as PNG (lossless, transparency-preserving) or JPG (92% quality, white-flattened).
Why a local overlay tool matters
Image overlay is often used for watermarking confidential mockups, stamping logos on pre-publication photos, adding "CONFIDENTIAL" badges to screenshots, or building double-exposure art from personal photos. Uploading the originals to a third-party tool just to composite is the worst place in the workflow to do that. ToolChop keeps everything local.
Blend mode quick reference
- Normal — straight alpha compositing
- Multiply — darkens (good for shadows, watermarks)
- Screen — lightens (good for highlights, glow effects)
- Overlay — contrasty mix of multiply + screen
- Difference — black where pixels match, colored where they differ
- Hue / Saturation / Color / Luminosity — transfer just that channel from the overlay to the base
Frequently asked questions
How do I overlay one image on another online for free?
Drop a base image, drop an overlay, pick a blend mode (Normal, Multiply, Screen, Overlay, Hue, etc.) and adjust opacity, scale, and position with sliders. The preview updates live as you tune. Click Download to save the composite as PNG (lossless) or JPG (92% quality). No account, no upload, no daily limit.
Does ToolChop upload my images?
No. Both images are loaded into a canvas in your browser, composited locally using the Canvas 2D blend-mode API, and exported in your browser. Your images never leave your device.
Why is the privacy story important for an overlay tool?
Image overlay is often used for watermarking confidential mockups, adding company logos to photos before sharing, creating signed-NDA stamps on PDFs/screenshots, or building double-exposure art from personal photos. All four are sensitive use cases — exactly the wrong places to upload originals to a third-party server. ToolChop keeps everything local.
What are the 16 blend modes?
Normal, Multiply, Screen, Overlay, Darken, Lighten, Color Dodge, Color Burn, Hard Light, Soft Light, Difference, Exclusion, Hue, Saturation, Color, and Luminosity. These are the standard W3C Compositing and Blending Level 1 modes — the same set Photoshop, Figma, and Sketch use.
When should I use each blend mode?
Multiply is great for shadows and darkening; Screen for highlights and lightening; Overlay for contrasty composites; Difference for finding pixel-level differences between two images; Hue/Saturation/Color/Luminosity for transferring just that channel from the overlay to the base. Normal is straight alpha compositing with opacity.
Can I overlay a transparent PNG logo on a photo?
Yes — this is the most common use case. Drop your photo as the base, your logo PNG as the overlay, use Normal blend mode with 100% opacity (so transparency is preserved). Use the scale slider to size the logo (10–30% is typical for corner watermarks), and X/Y offset to position it.
How do I make a double-exposure effect?
Drop a portrait as the base, a landscape or texture as the overlay. Use Screen or Lighten blend mode with 60–80% opacity. Tune the X/Y offset to align the overlay with the silhouette. Different blend modes produce different aesthetic effects — try Multiply for darker moodier composites.
Will the overlay preserve transparency?
Yes — PNGs with alpha channels are composited respecting their transparency. The blend mode applies only to the visible (non-transparent) pixels of the overlay. JPG output flattens the result against an implicit white background since JPG doesn't support alpha; PNG output preserves transparency from the base.
Does the output keep the base image's dimensions?
Yes. The base image's width and height are the output dimensions. The overlay is positioned and scaled within that frame. If you want a larger or differently-sized output, resize the base first (use the Image Resizer), then bring it back here.
Can I use this to find the difference between two images?
Yes — set the blend mode to Difference and opacity to 100%. Pixels that match between the two images appear black; pixels that differ appear as the color difference. This is the classic visual-diff technique used in QA workflows. For pixel-perfect diff, use the dedicated Image Diff tool.
Can I use this with screenshots?
Yes. Overlay a watermark, a logo, or a 'CONFIDENTIAL' badge on screenshots before sharing. Use Normal blend with ~50% opacity for subtle watermarks, or a sharp logo with 100% opacity in a corner. ToolChop runs locally so screenshots containing app UI or private data never travel.
Why use ToolChop instead of Photoshop, Figma, or an online overlay tool that uploads?
Photoshop and Figma require accounts and (Photoshop) a paid subscription. Online overlay tools that upload your files are a needless privacy risk for what is a Canvas 2D operation. ToolChop runs the composite in your browser with the exact same blend modes Photoshop uses — but with no install, no account, and no upload.