Unless you were financially dependent on your mother, and she was of sound mind when she made the will then you would not have any basis to contest it (assuming you live in england - the law may be different elsewhere) Your mum/dad had every right to leave their assests and personal property to whoever the chose (and indeed NOT leave anything to whoever they chose)
Legally you wouldbe entitled to anything that belonged to you, but how long ago was it? How do you know your stuff hasn't just been chucked out? Do you have specific things you want that were yours when you lived there? If so, you could try and get your aunt to ask for them, or write to your family and ask for specific things (what sort of things is it that you want?) As regards pictures, if they don't belong to you, you could try asking for them, but it dosen't sound like that will be too successful