[BUG] When using ImageBuf, this file reports a divide-by-zero exception error. Please take a look

**Describe the bug**

When using ImageBuf, this file reports a divide-by-zero exception error. Please take a look
This is a sample file.
[XPPen_new_logo.zip](https://github.com/AcademySoftwareFoundation/OpenImageIO/files/14567847/XPPen_new_logo.zip)

**OpenImageIO version and dependencies**
v2.4.13.0

**To Reproduce**

Execute the following code:
```
ImageCache *cache = ImageCache::create ()
auto inp = ImageBuf(path, cache);
if (inp.has_error()) {
std::cout << "parser: open image error: " << inp.geterror() << std::endl;
return nullptr;
}
```

**Evidence**

Reproduce the failure with the attached XPPen_new_logo.zip using the ImageCache and ImageBuf snippet in the issue. Start by tracing the ImageBuf construction and the reported divide-by-zero error in OpenImageIO v2.4.13.0. Done means the sample no longer produces the divide-by-zero exception and image-open errors remain appropriately reported.

Written by the indexing model from the issue text.