In our daily work, we often need to convert image formats, such as converting HEIC to JPG, or PNG to WebP. Traditional “online image conversion” services usually rely on an “upload-process-download” workflow.
This model is technically mature, but for users, it brings several unavoidable problems:
- Upload latency and failure: Uploading large files or bulk images is very time-consuming and is prone to interruption under unstable network conditions.
- Privacy and security risks: Users must upload original images (which may contain sensitive information) to third-party servers, creating a risk of leakage during data transmission and storage.
- Server processing bottlenecks: During peak periods, users may have to wait in line for the server to release resources.
We believe that for simple format conversion tasks, there is a better solution than server processing.
Browser-side Solution: WebAssembly (WASM)
To solve the above problems, we explored a new implementation method: Pure browser-based image conversion based on WebAssembly (WASM).
WebAssembly is a portable, low-level bytecode format that allows us to run code compiled from languages like C, C++, and Rust in the browser at near-native speeds.
We compiled the core image codec libraries into WASM modules. When users visit the service we call Convert something, these modules load and run directly in the user’s browser.
What is “wasm image convert”?
Simply put, wasm image convert technology means that all calculations happen on the local device.
The entire process is as follows:
- The user loads images via drag-and-drop or the file selector.
- The browser reads the image data into memory.
- The WASM module executes the conversion within the browser sandbox environment.
- The browser generates the converted image, which the user can download directly.
The image data never leaves the user’s computer from start to finish, perfectly solving the privacy concerns of traditional solutions.
Balancing Efficiency and Privacy: “privacy friendly convert”
The biggest advantage of this solution lies in its privacy friendly nature. Since calculations are performed entirely locally, we (as the service provider) do not need to access, process, or store any of the user’s image data.
This provides a high level of security assurance for processing images containing personally identifiable information, private photos, or scanned business contracts. This is a truly privacy friendly convert tool.
High-performance “Bulk image convert” Experience
The execution efficiency of WASM far exceeds that of traditional JavaScript, making it possible to implement bulk image convert in the browser.
Users can select dozens of images at once, and the WASM module will efficiently process these tasks in parallel locally, without the need for repeated uploads or waiting for server responses. Whether it is JPG, PNG, WebP, AVIF, or HEIC format, fast local mutual conversion can be achieved.
Technical Selection and Trade-offs
Of course, the pure browser-side WASM solution also has some limitations at this stage.
Due to the limitations of the browser environment and the size of WASM modules, this tool currently focuses on core format conversion functions. If users need advanced features such as watermarking, fine-grained compression quality adjustment, filters, or automated CDN delivery, the server-side SaaS solution still has more advantages at present.
We provide two options for different needs:
- Convert something: Suitable for
bulk image converttasks pursuing speed, privacy, and lightweight usage. - WebP Cloud: Provides enterprise-grade complete image processing workflows, cloud automation, and advanced optimization functions.
To improve the access experience, we have also added PWA (Progressive Web App) support for Convert something, which you can “install” to your desktop or home screen to achieve quick access closer to native applications.
We invite you to experience this pure browser-side image conversion tool: Convert something
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