Sticking with JPEG

In Atlantis, documents can include both text and pictures. Pictures can be inserted in two ways:

• You can use the Atlantis "Insert | Picture..." menu command and direct Atlantis to graphic files (GIF, PNG, JPEG, etc) located on your hard drive.
   
  
• You can also first copy a picture onto the Windows clipboard from some other application or from another document open in Atlantis itself, then paste the clipboard picture into the target document.
  

Now you might be curious as to how Atlantis stores pictures in documents, and rightly so, because it has practical implications.

When you save a document containing pictures in Atlantis, these are stored in the document file in either the PNG or JPEG format. It is very much like embedding PNG or JPEG graphic files directly into the document file. And when you close a document, then reopen it, the graphic format of each picture is retained within the document file as previously saved. If a document contains a picture in the JPEG format, Atlantis sticks with the JPEG format for that picture when you resave the document. Same thing for pictures found in the PNG format.

Even so, in practice Atlantis stores most pictures in documents in the PNG format. Pictures are stored as JPEG only when JPEG was their original format.

Atlantis offers no way to find out if the pictures included in a document are actually PNG or JPEG. This is because in most cases it is irrelevant which of the graphic formats is actually used by Atlantis to store a given picture within a document file.

But it is still possible to say which of the two graphic formats will be used by Atlantis to store a picture within a document:

• If you paste a picture from the Windows clipboard, most probably it will be stored by Atlantis in the PNG format.
   
  
• If you insert a picture through the "Insert | Picture..." menu command, it will be stored by Atlantis in the JPEG format if the graphic file that you insert is originally of the JPEG format.
   
  
• For graphic files of any other supported format than JPEG that you insert through the "Insert | Picture..." menu command, Atlantis will systematically use the PNG format.
  

Again, most chances are that an inserted picture will be stored by Atlantis in the PNG format.

But at times you might want to force Atlantis to store a given picture in the JPEG format instead. There is only one way to do this: have this picture in the JPEG format on your hard drive and use the Atlantis "Insert | Picture..." menu command to insert it.

You might ask, why would I want to force Atlantis to store pictures in the JPEG format?

If your picture is a "color-rich" painting or photo, it normally takes much less disk space if stored as JPEG. Converting a JPEG photo to the PNG format, nearly always leads to a much bigger PNG file. So if you have graphic files in the JPEG format on your disk, it is preferable to insert them AS IS through the Atlantis "Insert | Picture..." menu command. Most likely, this will create a more compact document file.

This remark holds for eBooks too. If you save a document as eBook in Atlantis, pictures stored as JPEGs within the source document file will be saved as JPEGs too in the eBook file. This might also significantly reduce the global size of the eBook file.

So if you designed a rich-color cover picture for an eBook in a graphic software, we recommend that you do not copy/paste the picture from the graphic software into an Atlantis document. It is because your cover picture will most probably be inserted into the document in the PNG format.

Instead, save the cover picture to your disk in the JPEG format from your graphic software. Then use the Atlantis "Insert | Picture..." menu command to insert the saved JPEG file into a document in Atlantis. If you then save the document as eBook in Atlantis, the cover picture will be stored within the eBook file as JPEG. Your EPUB file will only be lighter.