Editing Batches of Photos Easily on Linux - page 2
But before you Start, make sure you visit the tab labeled Output, where you'll choose an image format for your output images. The default is BMP, almost certainly not what you want. So set the output format to JPG (if you're creating images for the web), PNG, or whatever format you prefer.
Once you choose a format, you'll have some other choices (Figure 3). If you're not sure what any of that stuff is, just leave it at the default settings; they're probably fine.
Seeing the result
DBP doesn't offer live previews, but it does offer a Test button to show one preview window.
Don't let yourself be surprised if the preview is smaller than you expected. DBP usually seems to present its preview "zoomed out", so you may have to zoom in, using the Zoom Percent control in the lower left of the window, View->Zoom from the main menu, or the +/- keys. Or use my favorite GIMP shortcut: typing the numeral 1 presents the image at full 100% size.
You may notice that the preview window's titlebar includes the warning DBP internal - LOOK, DON'T TOUCH. Not only should you not make any changes in this window; you also shouldn't close it, or DBP gets confused, and you won't be able to test any further changes, nor produce the final images. If you need to close the preview window, use the Show Images button. Pressing it again brings the preview back.
When you're happy with your choices and ready to go, click Start to process all your images.
Wait -- one more trick. If you're starting with JPG files from a camera, and you're producing JPG files for the web, after you click Start you may see an error: Output files exist, please delete them! DBP saves images to the same directory where it found the input files; so if you're reading pict1510.jpg and then trying to save a modified version to pict1510.jpg, it sensibly refuses to overwrite your original image.
Solve that with the Rename tab (Figure 4). You can add a prefix or a suffix, or both. If you give it -web as a suffix, then pict1510.jpg becomes pict1510-web.jpg.
Okay, you're finally ready -- click Start and watch DBP do its work. You may get some error messages, like complaints about 'gimp-image-delete' if you have a preview window up -- but they don't seem to cause any real problem.
Then check your output directory. You should see your new files there, ready to use!