re: I set a custom size for the grid (image_width=’280′ image_height=’220′) but my images are croped and are not displayed correctly
The crop being applied to the images will be “Crop and resize proportionally to best fit the specified dimensions, maintaining the aspect ratio.” Meaning if you are uploading oversized images (larger than 280×220) then the image will be scaled down using the smaller dimension and then the larger dimension will be cropped based center of the image.
re: the different crop options in settings->images and it doesn´t work.
Those settings will not affect the images in the grid. The Large Image settings will affect the image displayed on the profile view of the template.
Hope that helps!
ps. Ensure you do not have errors in your shortcode, I supetct you do. Please follow the advice given here when working with shortcodes.