Problems in descompression file - Out of memory - flutter

Question

I have a sales app develpmented in Flex Builder. For use photos by off-line way, i upload a compressed file with all photos to the site and when need i sincronize with my smartphone. In that process is made a download to the dispositive and exist a responsable plugin to descompress the archive and disponibilize it in apropriate folder to later use.
That compressed file has 500MB size - 6700 photos approximately - and in Flex i have no type of problem to do that.
I'm rewriting the app in Flutter, using a archive package, dont getting the same results. In the descompress process i have problem with Out of memory.
Somebody already faced for something like that ?
Is there an best way to do this ?
I already tried other two alternatives:
- To use the Image.network, but, one of requires is work off-line.
- To save all the photos in assets folder, but i think that is not the best alternative, because the app will get bigger
Thank you in advance for.
Follow the error message and the code
code:
unarchiveAndSave()async{
var zippedFile = await initDir();
var bytes = zippedFile.readAsBytesSync();
var archive = ZipDecoder().decodeBytes(bytes);
for (var file in archive) {
var fileName = '$_dir/${file.name}';
if (file.isFile) {
var outFile = File(fileName);
print('File:: ${outFile.path}');
outFile = await outFile.create();
await outFile.writeAsBytes(file.content);
}
}
print('terminei de descompactar os arquivos');
}