If the Megapolis WP works inadequately, first of all, it would be wise to check whether it is installed to the correct folder. All theme files and folders must be stored here: …/wp-content/themes/dt-megapolis/ This theme is path-sensitive, so it will not work properly if it is installed to the folder …/wp-content/themes/megapolis/, …/wp-content/themes/megapolis wp/, etc.
Secondly, we suggest you to check whether the folders listed below have 755 CHMOD properties set: …/wp-content/, …/wp-content/themes/, …/wp-content/themes/dt-megapolis/
And finally, make sure …/wp-content/uploads/ (and all its children folders) and …/wp-content/themes/dt-megapolis/cache/ have 777 CHMOD settings.
Please do not forget to check whether your image size does not exceed hosting file size limit. You can find it next to “Maximum upload file size:” label on WordPress uploader tab.
If these steps give no result, please try deactivating all your plugins. The problem also can be related to the temporary address of your web-site which includes “~” symbol. But do not worry, as soon as you get a common address, everything will work correctly.