I've got a site running Zen Cart v1.5.4 (quite modified), IH-4, PHP 5.6.16, GD version "bundled (2.1.0 compatible)", PHP memory limit 128MB

All's been working quite nicely ... then a new product was introduced with an image that's 1,280,074 bytes (the previous largest one was 889,894 bytes). Attempting to (a) display that product in a listing, (b) display that product's details and (c) view that product's images in Tools->Image Handler-4 all result in a partially-rendered page with no debug-log generated.

I remember seeing a report of such an issue (perhaps by @delia) within the past year, but can't locate that posting now. Any suggestions on the proper corrective-action (other than resizing the image down)?