There are many applications available to reduce the size of images without losing quality. Most of these applications use image compression techniques to maintain image quality while reducing its size. Here is a general description of how these applications work:

1. Lossy image compression: These applications use lossy image compression algorithms such as JPEG or WebP. This algorithm analyzes the image and reduces its size by removing some detailed information that is not visible to the human eye. However, image quality is generally maintained.

2. Reduce resolution and trial resolution: These applications can reduce the resolution of an image or the number of pixels in it. This is done by resizing the image and reducing the number of pixels used to represent the image. Experimental techniques can also be used to reduce the size of an image while preserving its overall appearance.

3. Remove redundant data and improve compression: Applications can improve image compression by removing redundant data. This data includes redundant titles, unnecessary information, and additional information that is included in the image. By removing this data, the image size is reduced without affecting its quality.

Applications to reduce image size without losing quality rely on a set of advanced technologies to preserve important image details and reduce their size. You can find applications like "TinyPNG", "JPEGmini", "Optimizilla", "ImageOptim" and "Squoosh" that provide this functionality. The interfaces and options of these apps may vary slightly, so you can try several apps until you find the one that best suits your needs.