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5. Working with PhotoLine / 5.5 Working With JPEG-Files

### 5.5.2 JPEG-Images In PhotoLine

In order to allow lossless editing PhotoLine adds to every loaded JPEG-image the corresponding compressed JPEG-data. So long as the image data of a layer aren’t modified, these compressed data stay there. Whether there are attached data can be checked in the Layer Attributes dialog (see chapter 4.11). If there is an entry "Add. Picture Data: JPEG Picture", the JPEG-data are there. If a loaded JPEG-image is saved, the same compressed JPEG-data will be written, that were loaded before.

Now one may ask what should be the advantage of being able to save a file the same way it has been loaded. Well, it doesn’t have to be the same. There are several operations that can be applied without loosing the JPEG-data. These operations are:

- Rotation by 90°, 180° and 270°
- Mirror horizontally and vertically
- Change document information
Via Document Information (see chapter 7.4.80) metadata can be added and removed. The Document Attributes dialog allows to remove all metadata.
- Remove EXIF-data
The Attributes-dialog allows to remove the EXIF-data.
- Assign or remove an ICC color profile
An ICC color profile can be assigned or an assigned profile can be removed. This can be done with Set Color Profile (see chapter 7.6.12) or by using the Attributes-dialog.

When working with JPEG-files you should know a few simple rules in order to always get the expected result:

- The function Save always saves the existing JPEG-data. Changing the JPEG-compression in the file options doesn’t have any effect on Save.
- The function Save As saves the existing JPEG-data as long as they are smaller than the JPEG-data, that will be created by compressing using the current JPEG-options. So don’t be surprised, if changing the JPEG-compression only shows an effect when lowered under a certain value.
- The function Web Export works the same way as Save As.
- If Batch Converting uses the option Same as import as export format, existing JPEG-data will be written. If the export format is JPEG Picture, the behaviour will be the same as with Save As. This way it is possible to use Batch Converting to rotate JPEG-files lossless. But it is also possible to compress all files in given folder with a new JPEG-compression factor.
- Every function in PhotoLine handling files automatically works lossless with JPEG-files, even if it not listed here (for example Create HTML-File).
- The functions Rotate 90°, Rotate 180°, Rotate 270°, Mirror Horizontally and Mirror Vertically are slower than usual, if there are JPEG-data. If you find this annoying, you can delete the JPEG-data in the Attributes-dialog.