Site logo sometemes appear, sometimes doesn´t

Hello, I´m using the theme catch flames. I added a logo to the website using the panel at the left site in wordpres. The size of the logo is 290 x 45. When I visit the website for the first time, the logo doesn´t appear. There is only the alt text and the icon to see. When I visit the page second time, the logo appears. When I visit the page on other browser for the first time, the logo doesn´t appear. When I visit the page second time, the logo appears. This happen with other browsers as well. I named the image file representing the logo with upper case letters. I´m not sure if this relate to this issue. Is there any way to fix it? I made some other changes to the website. I don´t know, if these changes relate to this issue. I added another image next to the logo. I added image tag below the site details. I added another image above the site menu. This image take the full width of the page. I also made some other changes. I´m not sure if these changes relate to this issue. Can be these changes the core of the problem? Thank you for help.