Hi @ROBIN7, welcome to our community!
First of all you will need to check where these pictures and videos are stored in your phone. To do that you can open up the Album application > find the picture or video and tap on it. Now you should see only the video or the picture on your screen > tap once on the screen and 3 dots will appear in the bottom right corner, tap on them and choose "Details". You will now see the date when the photo or video was created, the file path to where the it's saved in your phone.
Once you have this information you can connect your phone to your computer and choose MTP mode so your computer can access the internal storage and SD card on your phone. Now you have 2 options, either you use the inbuilt file browser in your computer or you can download and install Xperia Companion and browse the internal storage / SD card from this program.
An example is a screenshot that you have taken in your device, the file path will be "storage/emulated/0/Pictures/Screenshots/xxxx.png.
Now when you browse the internal storage in your computer you will find the screenshot in the folder called "Pictures" in here you will see a sub folder called "Screenshots", when you open this sub folder up you will see all your screenshots.
Let me know if that helps! 
0online
1900810posts