Response to your issues as below
the thumbnail in the portfolio page, and the image in the project page are often distorted,is it possible to fix that ?
Yes, You can optimize the image sizes & projects page design styles based on the theme layout.
I'm not sure if it's the best way to do that, but I saw you don't use the thumbnail capability of wordpress, but it is very useful to resize images to display size :)
If it can help please see what I did: http://pastebin.com/xTDcVuRH
Default thumbnail capability ( small , medium, full ) array parameters will not return exact thumbnail image sizes. We can display image with specific image ( width x height ) from the image src. That's the reason, I have used image function.
Another little thing, if a project has no category, it can't be displayed by clicking on links, (when using "Post name" for permalink option).
the url look like this /wp-projects//projectname/ and results as a 404 error (/wp-projects/default/projectname/ is working despite the project is not in "default" category).
WP projects portfolio plugin is developed with category slug rewrite rules ,so you need to choose selective category for the particular portfolio item.
Hope I have cleared your responses.
So I'm closing this thread , let me know if you have any other issues & I'll be glad to assist you.
Thanks & have a gr8 day.