Only people who think fast find the letter in this image full of 7's

It is healthy and necessary to exercise your brain at regular intervals especially during these difficult times. Falling into the habit of exercising your body or mind is tricky. Having more fun than you would expect is a good challenge, and a perfect way to develop your skills.
You can find hundreds of thousands of challenges to test your abilities or just pass the time, thanks to the internet.
From classic riddles to math equations, it can be anything where you need to remember the rule of operations from your school days.
On top of that, few things feel as good as overcoming a mental trial alone!
Relaxing your mind by solving puzzles and brain exercises can sound a bit contradictory. The fact, though, is that they help you forget most of the things that make you worry or stress. Perhaps the most popular ones are crossword puzzles and sudoku, as they often appear in the newspaper. But nowadays, you no longer have to restrict yourself to one or two forms of puzzles, thanks to technology.
Need maximum concentration
One of the web's most popular challenges right now is to find specific details inside an image.
Can you figure out what letter stands out?
Here comes the challenge today.
Below you can see a picture with lots of 7s but a letter hides somewhere within the image. The problem you have is locating the message.
The picture comes here-can you find the letter?
It may not be easy but you should be able to solve it if you make an effort.
If you can't find it then see the picture below to find the answer.
Here's the answer
There's no question if you weren't seeing it; most of my peers couldn't see it either.
You can see the answer in the picture below.
There, a Z hides up in the corner. It's very much like a 7, but to find it was certainly not a walk in the park.
Congratulations on having discovered the elusive Z!
Now push the Sharing button below and see if it can be found by your mates too!