I have a php web page with 15 fields. The user will use it to upload images. I tested this by uploading 15 jpg images, each about 2 M, without any problems. On the day I launch, I will be moving this web page to another Linux shared hosting environment (still not sure which). Are there some web hosting environments that limit the size of total uploads in one http request?
Yes. There are (as far as I can remember) three or so configuration settings which will affect upload size restrictions:
upload_max_filesize, which sets an upper limit on the size of uploaded files
post_max_size, which limits the total size of posted data, including file data
max_input_time, which restricts the length of time the script is allowed to process input data, including posted values
upload_max_filesize is a limit on each individual file; however,
max_post_size is an upper limit on the entire request, which includes all the uploaded files.
Different hosting environments will have these values set differently, which may affect your abilities upon deployment.