WiFi & display advice needed

I need to do a simple project that connects via WiFi to a web server and periodically downloads an image to display on a small screen. Due to the memory on the arduino’s I was planning to either stream the image directly to the display or save it to an SD card first and then display from there.
I will end up needing about 100 in total so need to keep the complete price down as low as possible.

So far I have been trying to use the following components

Arduino uno (using mega for debugging due to extra serial ports)

2.4” TFT display with SD slot http://www.ebay.com.au/itm/172014802299?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

grove uart wifi (SP8266 based) http://www.seeedstudio.com/depot/Grove-Uart-Wifi-p-2495.html

Image display from SD card works fine as does the touch display. However when it comes to the WiFi I’m having problems getting the image. I can connect to a server and start downloading the image but I can only ever receive the first part of the image. All the WiFi samples seem to assume a small amount of data and once it goes over a certain size the rest is lost, looks like there should be multiple +IPD packets but I only ever seem to revive the first one.

So I was wondering if anyone had experience accessing larger files over WiFi or if they could suggest a different WiFi module that would be easier to work with. I was looking at getting the seeeduino wifi shield http://www.seeedstudio.com/depot/Wifi-Shield-V20-p-2505.html or a CC3200 based device but was hoping not to spend weeks waiting for them to arrive just to find out I had problems with them as well.

So any ideas? I've orders a yun to see if that will work but starting to push the price up a bit much