Compressing Images to an Exact File Size Limit in the Browser with canvas.toBlob

A developer working on the QuickImgTools site describes a browser-based method for compressing an image to stay under an exact kilobyte limit. The approach uses canvas.toBlob to encode the image at different JPEG or WebP quality levels, then applies a binary search to find the highest quality that still fits the target size. If quality reduction alone is insufficient, the method scales down the image dimensions by a square-root ratio tied to the target size. The article also covers edge cases, such as PNG files that ignore quality settings and minimum dimension limits, along with step-down resizing to avoid soft or aliased output. The method is presented as a way to meet hard file-size requirements common in upload forms without manual trial and error.