I would like to hire a WordPress Developer to fix issues with an existing site

We have an existing WP website created by developers. It is functional but has a number of issues, plus we would like some additional functionality. Issues and additional Functionality required: There appear to be number of issues with the master CSS - mostly formatting but this might be the cause of some of the other issues listed below. Media - when images added to text sections, the images always revert to full page width even when set to left aligned and a specific size. Entering HTML in the text editor doesn't help as it seems to be superceded by the CSS. Calendar - existing calendar could do with a bulk uploader. Replacement of calendar with a google calendar plugin would be ideal. Images - We seem to have a 2mb upload limit for files. Image quality across the site varies and the same images can appear pixelated on desktop versions but ok on phones / tablets. This is partularly evident with featured images at top of pages where some fit properly, and others do not - and image quality is poor. We have also tried using other third party plugins, particularly with a Flickr plugin which fails because of the way the Java Script calls happen. which needs investigation and a fix.