How bad is the quality? Uploading photos to Instagram or Twitter compresses them reducing their quality, but they still should look somewhat good. If you're trying to upload 108mp photos to Instagram that won't work very well at all.
Are you taking photos using the Instagram stories feature? Instagram doesn't fully utilize Android cameras to their full extent so photos taken/uploaded there are significantly worse quality than iPhones using the same feature. If you're trying to upload a 108mp photo from your gallery to Instagram, it will be heavily compressed and there's no real way around that.
