Merge branch '2.2' into 3.1

# Conflicts:
#	CHANGELOG
#	conf/gns3_server.conf
#	gns3server/compute/docker/__init__.py
#	gns3server/compute/docker/docker_vm.py
#	gns3server/compute/qemu/qemu_vm.py
#	gns3server/controller/import_project.py
#	gns3server/crash_report.py
#	gns3server/version.py

gns3server/controller/import_project.py

@@ -295,14 +295,19 @@ async def _import_images(controller, images_path):
     for (dirpath, dirnames, filenames) in os.walk(root, followlinks=False):
         for filename in filenames:
             path = os.path.join(dirpath, filename)
-            if os.path.islink(path):
-                continue
             dst = os.path.join(image_dir, os.path.relpath(path, root))
             os.makedirs(os.path.dirname(dst), exist_ok=True)
             if not os.path.exists(dst):
                 await wait_run_in_executor(shutil.move, path, dst)
-                os.chmod(dst, stat.S_IWRITE | stat.S_IREAD | stat.S_IEXEC)
-
+                try:
+                    with open(dst, "rb") as f:
+                        # read the first 7 bytes of the file.
+                        elf_header_start = f.read(7)
+                        # IOU images must start with the ELF magic number, be 32-bit or 64-bit, little endian and have an ELF version of 1
+                        if elf_header_start == b'\x7fELF\x01\x01\x01' or elf_header_start == b'\x7fELF\x02\x01\x01':
+                            os.chmod(dst, stat.S_IWRITE | stat.S_IREAD | stat.S_IEXEC)
+                except OSError as e:
+                    continue
 
 async def update_snapshots(snapshots_dir, project_path, project_name, project_id, reset_mac_addresses=True):
     """