Thank you very much for your answer. This partially helped me. After I added the the description to the file the ALT atribute appeard on the subpage itself. But, on the part where I see the titles of the sub-pages I can see, as a preview the images as well, but on the source code there is no ALT description...
The concrete example: <p style="text-align:justify"><span style="color:#0070c0; font-family:tahoma,sans-serif">I saw a lot of candidates who prefer to add a photo to the CV – I think everyone can agree that as long as the photo is one business-appropriate this is an Yes – Yes situation, but when the photo just reflects your look when you were 5 years younger and ready for a night out, I guess you can just drop the idea – no matter how beautiful your smile is in that picture, you do not want to scare the employer or just be the part of the joke of the day – keep it professional or if you do not have anything that can go with you – just forget about it; hopefully there will be many occasions in which you ca show how funny and interesting you can be.</span> </p> </div><ul class="pages-list"><li><h2><a href="?ok-so-you-made-your-mind">Ok, so you made your mind...</a></h2></li><li><div class="image"><a href="?the-taste-after-bilingual-people-international-language-recruitment-fair-krakow-25th-april-2015"><img src="files/200/language_fair.jpg" alt="" /></a></div><h2><a href="?the-taste-after-bilingual-people-international-language-recruitment-fair-krakow-25th-april-2015">The taste after Bilingual People International Language Recruitment Fair, Krakow, 25th April, 2015</a></h2></li><li><div class="image"><a href="?here-we-go-–-our-first-event!"><img src="files/200/valiza.jpg" alt="" /></a></div><h2><a href="?here-we-go-–-our-first-event!">Here we go – our first event! </a></h2></li><li><h2><a href="?we-think-that-looking-for-a-job-deserves-to-be-a-journey-with-a-happy-ending!">We think that looking for a job deserves to be a journey with a happy ending!</a></h2></li></ul></article>
Talking about "files/200/valiza.jpg" alt="" and "files/200/language_fair.jpg" alt=""
Please note that this is the source code that I can see on my browser. The thing I am looking for is the file in my c-panel (on the server). Can you advise me which one is ?