Trouble uploading images to galleries

I cannot upload any images to a gallery. When I try to upload multiple images (4-6) I get the icon that indicates it is working but never gets past that point. I’ve reduced the size of the images considerably with no success, I’ve tried changing the resolution with no success. I’m using ver 3.4.2 so it’s not an issue with an older version or update and I only have one plug-in so far. This was working (sort of) when I was first up and running, When I tried to upload multiple images it would only upload about half and the rest would just fail to complete – I thought I had tried to upload too many / too large, so I downsized everything, but now I can’t upload anything. I’m new at this so can anyone give me some easy to understand suggestions