I have found out, that, if I insert image over cells in spreadsheet, then it works and I get that image on final merged PDF. If I set image as in cell. Then it does not work. So solution is found. Set images over cells, do not place it in cell.
I also want to mention that I cannot use slides or docs on this purpose, as from merged spreadsheet calculations is made and report with charts are prepared, so other solutions do not provide that functionality. After all that Autocrat create pdf what is sent to client as report of Google forms survey.
Important to mention that numbers from data into template sheet is imported as text. If somebody need to have calculations after merge, You need to use =value(cell reference) in formula to use it as number.
Aleksandrs