Web developers often face the challenge of compressing images to meet specific size requirements, such as a 100KB limit for uploads. The traditional approach involves manually adjusting image quality settings through trial and error, which is inefficient and unreliable. This article introduces a more effective method using binary search to precisely compress images to a target size. The author explains that the quality slider commonly used in image compression tools is a poor primitive because the same quality setting produces vastly different file sizes depending on the image content. Instead, the target-first approach focuses on the desired file size (e.g., 100KB) and finds the highest quality that fits within that budget. The technique involves drawing the image to a canvas, then performing a binary search over the quality axis (typically 8 iterations) to find the optimal quality setting. The algorithm ensures that the resulting image is as high quality as possible while staying within the size limit. The author provides a JavaScript function that implements this method, which can be used directly in web applications. Additionally, the author created a free browser-based tool called ‘Compress Image to 100KB’ that automates this process, allowing users to drop in an image and get a compressed version that fits their size requirements without any guesswork. The tool operates entirely in the browser, ensuring privacy as images are never uploaded to a server. The article concludes by asking readers about their own image compression practices, including target sizes and whether they compress at upload time, build time, or via a CDN. This method represents a shift from the common practice of compressing defensively (using lower quality settings to ensure size limits are met) to a more precise and efficient approach that maximizes image quality within constraints.