Who will explain me how to make a posted picture bigger?

there is limitation with this forum (the script). so, any size will shrunk to the max size allowed set by admin. but that is just for viewing, the original image (source) is not affected.

if you need to see the picture bigger, you can (for Windows) :
[*]open it in new tab and see if the original picture actually bigger.
right-click open image in new tab

[*]Ctrl + Mouse Scroll (in and out) for zoom function.
press and hold Ctrl button on keyboard, Scroll in and out your mouse

If one needs to make a picture ( or in this case, a screencap ) bigger, you'll be needing an image editing program -- there are many free and open-source programs to get from reputable publishers, as well as commercial-trial ones ( sorry, can't link the sources, just use the search engine with the keywords of the publisher's and their programs to get to their main sites ):

For Free/Open-source -- there's The Gimp Team's GIMP, Rick Brewster's PAINT.Net, Irfan Skiljan's Irfanview, Mooli Tech's Photoscape

For Commercial Trial* -- there's ACD System's ACDSee, Adobe Systems's Photoshop and Lightroom, Axel Rietschin's FastPicture Viewer, and Corel Corporation's PaintShop Pro

* Remember then when using/installing a commercial-demo program, it's good to use for a limited time ( this depends from a few usages, to at least 10-15days from the day it was installed ) and once the limitations had been reached, the program must be uninstalled completely

Thank you very much dukuntekno and oberder