Base64 Code not rendering for huge Image

Hi,
I´m using the function to create a Base64 String:

`public static String convertToBase64(File file) throws IOException {

LOGGER.info("START convertToBase64");

InputStream finput = new FileInputStream(file);
byte[] imageBytes = new byte[(int) file.length()];
finput.read(imageBytes, 0, imageBytes.length);
finput.close();

String result = Base64.encodeBase64String(imageBytes);

LOGGER.info("END convertToBase64");
return result;
}`

If I have images which a bigger (4 MB) than OpenHTMLtoPDF is not rendering those images anymore.
For images which are not so big (1 MB) it´s working fine.
In the HTML page is rendering fine.

Any ideas?