einfachannett – the blue accents are used in many places in Pictorico. You could start with the grid box background colour, as I’ve shown someone else here:
https://www.ads-software.com/support/topic/change-thumbnail-background-color?replies=4#post-6088815
Other blue elements include links and the site title, for example. To modify those, you could add some custom CSS to your custom CSS plugin or child theme:
a, .site-title a {
color: #bb00bb;
}
You can add additional elements whose colour you’d like to change to this code by separating them with commas, and of course you can change bb00bb to any hex colour you like.
To find other elements that use the default blue colour, you can look at the stylesheet for instances of #07a1f2, or use a browser inspector to identify the element. Here are some very helpful posts that will help you customize your site with CSS:
https://dailypost.wordpress.com/2013/07/25/css-selectors/
https://dailypost.wordpress.com/2013/06/21/css-intro/
https://dailypost.wordpress.com/2013/08/29/css-matched-rule-pane/
https://en.support.wordpress.com/custom-design/how-to-find-your-themes-css/
If CSS is new to you, here are some resources for learning more about it: