You have two way to post pictures:
1). If the picture from you PC then click on the blue Russian sentence just above you writing window Добавить картинку в сообщение
A new window will open on your PC.
You can download either from your PC - С компьютера | Из интернета
Or from the internet - С компьютера | Из интернета
You need to choose and click.
2. If you download from your PC
- click on the Russian word Обзор - View
- if the picture is too big you can chose the size in the next little frame one step lower.
- if the picture is a ok just click at the bottom on the Russian word Загрузить - download.
Alternatively you can download pictures by clicking on the icon with Madonna - above on your left of you posting window and you get an image brackets - just add the address of the picture.