┌──(kali㉿kali)-[~/code]
└─$ strings cat.jpg | grep "pico"

...Nothing

┌──(kali㉿kali)-[~/code]
└─$ exiftool cat.jpg
ExifTool Version Number         : 12.57
File Name                       : cat.jpg
Directory                       : .
File Size                       : 878 kB
File Modification Date/Time     : 2021:03:15 14:24:46-04:00
File Access Date/Time           : 2023:08:03 02:47:30-04:00
File Inode Change Date/Time     : 2023:08:03 02:47:30-04:00
File Permissions                : -rw-r--r--
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
JFIF Version                    : 1.02
Resolution Unit                 : None
X Resolution                    : 1
Y Resolution                    : 1
Current IPTC Digest             : 7a78f3d9cfb1ce42ab5a3aa30573d617
Copyright Notice                : PicoCTF
Application Record Version      : 4
XMP Toolkit                     : Image::ExifTool 10.80
License                         : cGljb0NURnt0aGVfbTN0YWRhdGFfMXNfbW9kaWZpZWR9
Rights                          : PicoCTF
Image Width                     : 2560
Image Height                    : 1598
Encoding Process                : Baseline DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:2:0 (2 2)
Image Size                      : 2560x1598
Megapixels                      : 4.1

*DESCRIPTION. A command-line interface to Image::**ExifTool**, used for **reading and writing meta information in a variety of file types**. FILE is one or more source file names, directory names, or - for the standard input.*

┌──(kali㉿kali)-[~]
└─$ python3                                                                                     
Python 3.11.2 (main, Mar 13 2023, 12:18:29) [GCC 12.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import base64
>>> base64.b64decode(b'cGljb0NURnt0aGVfbTN0YWRhdGFfMXNfbW9kaWZpZWR9')
b'picoCTF{the_m3tadata_1s_modified}'

then use Python to decode it