Save and Save as save the current picture in a file. Save uses the current name. If the picture doesn’t have a valid filename, Save as... will automatically be used.
Save as... shows the file select dialog and asks for a name for saving the picture. You can choose the file format for saving with File Type. But you can also change the file format by simply appending the corresponding extension. I.e. if the name "Test.tif" is entered, the picture will be saved in the TIFF-format, even if File Type is set to different format.
The Options-button allows to adjust the settings for the given format (see chapter 7.10.1).
If Remember Save Path is selected, calling the next time Save as... will not preselect the folder the document was loaded from, but that, that is chosen during the current Save as....
No file format - with the exception of the PhotoLine-Format PLD - is able to store all possible features of a picture (some are not able to store layers, others can’t save text, ...). Therefore, PhotoLine is saving a reduced version of the picture, if the format is not able to save all features. The reduced version normally looks the same as the original, but it doesn’t contain all data anymore (i.e. the text layers have been converted to images or the whole document has been converted to one image layer). With Options/File (see chapter 7.10.1) you can adjust, how the original is reduced and whether PhotoLine warns you before reducing.