How are you?
Try turning off wi-fi and enabling mobile data as sometimes that makes it work. If not text the word settings to 2020 then install the download.
If this doesn't work install the settings manually into your phone.
Mms cost 16p each to send and are not included within your goodybag allowance.
Therefore you will need airtime credit and you can do this by visiting this link : https://giffgaff.com/buy .
You could also send pictures via apps like WhatsApp which you can download from the app stores.
Hope this helps