Preview increases the size of a tiff file created by epson scanner when manipulating it and saving

I have an Epson scanner and i have scanned a photo to my mac book pro. I am running macOS BigSur 11.6.7. Finder is showing the size of the resulting .tiff file as 6.2mb. I wanted to select a portion of the photo and then create a new .tiff file from the selection. Here is what I did 1. I opened the scan photo in the preview app. 2. I selected the portion of the image I wanted to create a new file out of. 3. Copy the selected portion. 4. Cmd N, this open a new tab which contains the copied portion of the image. 5. I saved the new file with a different name. The size of the new file is 30mb. Now, I was expecting the new file to have a size much smaller than the original. **What is happening? Why is the new file so big?**