Short version: open the free tool, drop your file, download the result. Nothing is uploaded.

Steps

Open the free WBS Image Compressor.
Tap the 100 KB preset (or choose Target size and type any number, like 50 or 20).
Drop your photo onto the page, or click to choose it. You can paste a screenshot too.
Check the new size and pixel dimensions in the table, then press Download.

Why "under 100 KB" is tricky

File size depends on the number of pixels and the compression quality. A phone photo is usually 2 to 5 MB with 12 million pixels, so getting it under 100 KB takes both lower quality and fewer pixels. The compressor tries the highest JPG quality that fits first. Only if that isn't enough does it reduce the dimensions, step by step, until the photo fits.

Tips for forms with strict rules

Need specific pixels too? Set Max width (for example 600) before you drop the photo. For exact width and height, use the converter & resizer first.
Format: most forms want JPG. Choose JPG under Format if your original is PNG or WebP.
Very small targets (20 KB): expect a smaller image. A passport-style headshot at 300 to 400 px wide usually fits with good quality.
Discord or email limits: use the 20 MB or 2 MB presets to keep quality high (see compressing for Discord and shrinking photos for email).

Why not just use any online compressor?

Most online compressors upload your photo to their server. For an ID photo or a signature scan, that's a privacy risk you don't need. The WBS compressor runs in your browser, so the photo never leaves your device. The free version handles up to 20 photos at a time; WBS Tools Pro ($7 once) adds unlimited batches and a ZIP download.

More free guides

All tools: WBS Tools · All apps: Wood Between Studio apps