Using JPEGs in Blocks and Stacks
All About Image Blocks and Image Stacks
When an image is dragged into Blocks or Stacks it is converted
to a decompressed bitmap. This is to speed up things like scaling,
dragging, and moving. To help things get around in real time it's
easiest not to work with a JPEG.
This conversion means that we're left with a new original format. And one that's much closer to PNG. So all Image Blocks and Image Stacks have PNG as their original format.
How do I import a JPEG?
You can drag any Mac OS X supported image format (which is nearly everything). However, as mentioned above, all images will be converted to a PNG. That process will not degrade the image quality of a JPEG, but may increase its size.
How do I export as JPEG?
Blocks and Stacks respect the export settings in the Page Inspector under the Info tab. You can set the Image Format to Original, JPEG, and PNG.
In Blocks you can, additionally, double click on the image and specify that a specific image overrides the page default.
Small jpg files turn into huge kb file sizes
PNG can use some compressions but it's non-lossy which means that it generally results in higher quality, larger images. Converting to JPEG is recommended for all images that don't require transparency.
If the image that's dragged into Blocks or Stacks is already highly compressed then there there is a very good chance that decompressing it into a bitmap and then re-compressing it into another JPEG will result in a substantial loss in image quality. For this reason it's always best to start with the highest quality image you have.
Fine tuned control
If you need to maintain control over an image then you can drop it directly into a Text Block to create an inline image. The RapidWeaver text system will not modify images so long as you don't scale or otherwise modify it. You must then also set the page to export the image as "Original". This is a good option for preserving GIF images.