easy way of uploading images

Change the permissions of your upload directory to 777 (CHMOD 777).

I feel stupid, but I don’t know how to do this…
Can you help?

This should help: https://www.tamba2.org.uk/wordpress/ftp/

If you don’t have shell access via telnet or SSH, you may not be able to directly execute the chmod command. If not, then you may be able to chmod the directory using your ftp client software. I use the open source FileZilla, and it allows you to set Read/Write/Execute privileges on directories and files.

Thanks everyone, I’ll try and let you know if I can manage it.

Well, thanks for all the tips. Thanks to you, I did download Filezilla and executed the chmod command. Then I found that my usual ftp client could do it too. Then I read in another post about a plugin that made it easy to upload images at
https://www.bistr-o-mathik.org/code/wordpress-plugins/
I downloaded it and I think this is all going to help me a lot.