2. 制作网络用途的图片

GIMP最常用的一个功能就是为网站制作图片。这要求图片要尽可能的漂亮同时图片尺寸又要保持尽可能的小。本向导展示了如何创建小尺寸的图片同时又能保证图片的质量。

2.1. 拥有良好文件大小和图片质量比的照片

一个良好的网络图片取决于图片的类型和图片文件的格式。使用JPEG做为照片的格式,因这照片通常含有许多颜色和大量的细节。拥有少量颜色的图片,比如按键、图标或者是屏幕截图,则使用PNG格式更为合适。

  1. 首先,按正常方式打开一幅图片,我已经打开了Wilber作为示例图片。

    图 6.8. 以RGBA的模式打开图片Wilber

    以RGBA的模式打开图片Wilber

  2. 图片当前处于RGB模式,同时还有另外一个Alpha通道(RGBA)。通常在网络图片中不需要alpha通道,可以通过合并图层来去掉alpha通道。

    通常的图片没有alpha通道,图片会以RGB的模式打开,而不是RGBA模式,因此这种情况下就不需要去手动删除alpha通道。

    [注意] 注意

    If the image has a soft transition into the transparent areas, you should not remove the alpha channel, since the information used for the transition is not be saved in the file. To export an image with transparent areas that do not have a soft transition, (similar to GIF), remove the alpha channel.

  3. 在合并图层后,以sPNG格式导出图像作为网络图片。

[注意] 注意

You can export your image in the PNG format with the default settings. Always using maximum compression when creating the image. Maximum compression has no effect on image quality or the time required to display the image, but it does take longer to export. A JPEG image, however, loses quality as the compression is increased. If your image is a photograph with lots of colors, you should use jpeg. The main thing is to find the best tradeoff between quality and compression. You can find more information about this topic in 第 1.2.3 节 “Export Image as JPEG”.