In order to compress your photos as much as possible without any loss of photo quality, the WinZip compression setting should be Zipx: Best method. If you switched interfaces so that you are using the Legacy menus/toolbar setting, the compression setting will be Zipx: Best method (smallest size). The Legacy interface is the default for Windows XP.
With WinZip, "Best method" compression examines each file and selects the compression option most likely to supply the best compression results. If you are adding JPEG/JPG images (photos), WinZip 12 or later will use Jpeg compression. If you add other file types, WinZip will use different compression methods including LZMA, PPMd, WAVPACK and others.
When you use advanced compression methods, the result will be a .zipx file and your recipients may need WinZip 12 or later in order to open it. As always, WinZip's .zipx enhancement to the Zip file format has been published. This provides details regarding the implementation of these new compression methods on our website. Some utilities have implemented these changes and we hope and expect that developers of other Zip file utilities will also include support for these formats in the future.
Feel free to encourage your recipients to download and install the latest version of WinZip and use it free during the evaluation period. This will allow them to open your Zip files compressed with "Best method" and take advantage of the faster transmission and download time, and more efficient use of disk space.
If you have any questions about this information please email Technical Support.
Default compression - What it is, how to change it
What is the difference between "Legacy" and "Best method" compression?
What is a Zipx File?