What

MergePNG is a free, client-side web utility designed to combine PNG, JPG, and WebP images into a single image or PDF document directly within the user's browser. It serves professionals and general users who need to organize visual assets, such as screenshots or contact sheets, without transmitting sensitive files to third-party servers. Positioned as a privacy-focused alternative to server-side image processors, it executes all rendering, scaling, and format conversions locally using the HTML5 Canvas API.

Features

Client-Side Canvas Processing: Decodes, composites, and exports images locally with full alpha-transparency preservation and zero network uploads, allowing the tool to operate entirely offline.
Mixed-Format Ingestion and Export: Accepts combinations of PNG, JPG, and WebP files in a single merge and exports the unified output to PNG, JPG, WebP, or PDF.
Configurable Layout Templates: Offers preconfigured compound layouts, grids, and directional stacks alongside granular controls for gaps, margins, alignment, borders, and corner radii.
SHA-256 Duplicate Detection: Computes content hashes for incoming files to identify and flag byte-identical duplicates before rendering begins.
Browser Limit Safeguards: Evaluates canvas dimensions against device constraints—such as iOS Safari's ~16.7 million pixel cap—and scales the output down to prevent silent rendering failures.

Helpful Tips

Export Format Selection: Choose PNG or WebP when background transparency must be retained, as selecting JPG will automatically flatten transparent alpha layers onto a solid white background.
Mobile Canvas Management: Account for mobile memory constraints during high-resolution merges, as mobile browsers will automatically scale down large dimensions to fit device canvas caps.
Privacy Verification: Disconnect the device from the network after the page loads to verify that data processing remains strictly local during sensitive image workflows.

OpenClaw Skills

The source documentation does not list any native integrations, APIs, or official connections to the OpenClaw ecosystem. In a hypothetical implementation, an OpenClaw browser-automation skill or agent could interface with the web interface to batch-assemble sequential application screenshots into standardized visual audit logs or documentation sheets. This approach could streamline reporting workflows for quality assurance and technical documentation teams while maintaining local data custody.