이미지 크기를 줄이지 않고, 이미지의 파일 크기를 줄일 수 있습니다. 가장 널리 사용되는 압축 이미지 형식은 JPG으로, 이미지가 이미 JPG 형식이라고 하더라도 압축 레벨을 조정하여 이미지 파일 크기를 줄일 수 있습니다. 하지만 이미지를 압축하면 이미지 화질이 떨어질 수 있기 때문에 주의하여 적정한 값으로 압축해야 합니다. 또한 JPG 형식으로 압축을 반복하면 이미지 화질이 계속 떨어진다는 점에 유의하세요.

Since GIMP-2.8, images are loaded and saved as .XCF files. Your JPG image has been loaded as XCF. GIMP offers you to Overwrite image-name.jpg or File → Export As to open the “Export Image” dialog.

The dialog opens with the file name already typed in the Name box, with the default.png extension. Delete the existing extension and type JPG instead, and GIMP will determine the file type from the file extension. Use the file extension list, red circled in the figure above, to see the types supported by GIMP. The supported extensions change depending on your installed libraries. If GIMP complains, or if “JPEG” is grayed out in the Extensions menu, cancel out of everything and step through the 4.7절. “모드 변경하기”. Once you have done this, click Save. This opens the “Export Image as JPEG” dialog that contains the quality control.

The “Export Image as JPEG” dialog uses default values that reduce size in memory while retaining good visual quality; this is the safest and quickest thing to do.

Reduce the image Quality to make the image even smaller. Reduced quality degrades the image, so be certain to check “Show preview in image window” to visually gauge the degradation. A Quality setting of 10 produces a very poor quality image that uses very little disk space. The figure below shows a more reasonable image. A quality of 75 produces a reasonable image using much less disk space, which will, in turn, load much faster on a web page. Although the image is somewhat degraded, it is acceptable for the intended purpose.

다음은 압축 정도에 따른 이미지의 화질 상태 비교입니다.