Google Sheets – Reformatting Text Strings with Google Apps Script

The answer is yes. Google Sheets, Docs, Slides and Photos (partially - if downsized) are not counted against Drive space. While inserting images into Docs, Sheets... may sound like a loophole, from a long run it's not very flexible. Inserted images in Sheets tend to broke and dropping too many files into the document will significantly increase the load time eg. slow down the document up to the point when Google document may crash. Another disadvantage would be the limited upload of 1 image at a time.

Also, note that initial files stay on your Drive after conversion, so you will need to delete them.

You're basically wanting to format a date.

I would act on the JavaScript Date object, something like:

var startDate = new Date(row[5]);
var weekDay;
switch (startDate.getDay()) {
  case 0: weekDay = "Sun"; break;
  case 1: weekDay = "Mon"; break;
  case 2: weekDay = "Tue"; break;
  case 3: weekDay = "Wed"; break;
  case 4: weekDay = "Thu"; break;
  case 5: weekDay = "Fri"; break;
  case 6: weekDay = "Sat"; break;
}
var month;
switch (startDate.getMonth()) {
  case 0: month = "Jan"; break;
  case 1: month = "Feb"; break;
  case 2: month = "Mar"; break;
  case 3: month = "Apr"; break;
  case 4: month = "May"; break;
  case 5: month = "Jun"; break;
  case 6: month = "Jul"; break;
  case 7: month = "Aug"; break;
  case 8: month = "Sep"; break;
  case 9: month = "Oct"; break;
  case 10: month = "Nov"; break;
  case 11: month = "Dec"; break;
}

var formattedDate = weekDay + " " + month + " " + startDate.getDate() + " " + startDate.getFullYear();

The variable formattedDate now holds a string like Fri Feb 20 2015.

If you want to do this by manipulating strings instead, and you're not concerned with the language settings of the spreadsheet, you could use

var startDate = row[5] + "";
var formattedDate = startDate.substring(0, 15);