This time using find to discover a flag is not so trivial, in fact the pic is not the real ones.
root@ip-10-0-101-252:~# find /* -name '*.png' | grep hearts
/lost+found/3_of_hearts.png
/var/www/html/drupal/sites/default/files/styles/large/public/field/image/5_of_hearts.png
/var/www/html/drupal/sites/default/files/styles/thumbnail/public/field/image/5_of_hearts.png
/var/www/html/drupal/sites/default/files/field/image/5_of_hearts.png
Using Exiftool we have a little hint:
Stone:Flags syrion$ exiftool 5_of_hearts.png
ExifTool Version Number : 10.65
File Name : 5_of_hearts.png
Directory : .
File Size : 497 kB
File Modification Date/Time : 2017:12:06 12:19:58+01:00
File Access Date/Time : 2017:12:06 12:30:27+01:00
File Inode Change Date/Time : 2017:12:06 12:21:37+01:00
File Permissions : rw-r--r--
File Type : PNG
File Type Extension : png
MIME Type : image/png
Image Width : 500
Image Height : 700
Bit Depth : 8
Color Type : RGB with Alpha
Compression : Deflate/Inflate
Filter : Adaptive
Interlace : Noninterlaced
Tag 5 of hearts : iVBORw0KGgoAAAANSUhEUgAAAfQAAAK8CAYAAAAZNU0WAAAAAXNSR0IArs4c6QAAQABJREFUeAHsvQecX8lV51udc5C61cpxosOATVwMNsFkP++CWT6Gt8suLB/AvCUsyYTPsh/AwIM1uyzZZBYesMvaBJtgY2PPjCbPSBqlGUkjaUZxlGNLnbvf93vqf1v/bvVoZuzB05qp6nDvrVvh1Kl7z6/OqVN1G9LLGPbu3Ts4PtXwxpmGmTsaU7pjJv5mVkBSTwN/aSb1ENf6Mp...
The actual flag is in the base64 data:
exiftool 5_of_hearts.png | grep tag | cut -d " " -f 22 | base64 -D > real_5_of_hearts.png
MD5 = 1862c5dac75e43bb8d530d54575592b7