Attach Images to Post + small gallery in WordPress

We need a Plugin for WordPress which lets registered Users attach an image to a post and a page where all the uplaoded images are display with thumbs. But here's the twist: The User has a normal »subscriber« role and has to upload the image from the frontend of the blog, not /wp-admin/ ! So if »domain.tld/post« is the blogpost, »domain.tld/post/upload-image« is where the upload form is. On that site, a user can upload up to 5 images. »domain.tld/post/images« is where all images are display with thumbs, thumbs link to big image (can be direct-link to .jpg/.png). Some more specs: - Only .jpg and .png are allowed! - Size of the image should be set in admin - Error message on »domain.tld/post/upload-image« if an image is too large or wrong size. - Extra Code where we can display an image (just one) next to it's post within a category/archive. - Use WordPress Thumbnails - Security is important!