TestHDFViewImageConversion: convertImageToHDF4 fails - HDF4 image conversion bug

## Description
The `convertImageToHDF4` test in `TestHDFViewImageConversion` fails when attempting to convert a JPEG image to HDF4 format. After conversion, the file tree shows 0 rows instead of the expected converted file.

## Error Details
```
The row number (0) is more than the number of rows(0) in the tree.
```

## Test Details
- **Test file**: `TestHDFViewImageConversion.java`
- **Test method**: `convertImageToHDF4()`
- **Input image**: `apollo17_earth.jpg`
- **Expected output**: `apollo17_earth.jpg.hdf`

## Steps to Reproduce
1. Run `mvn test -pl hdfview -Dtest=TestHDFViewImageConversion#convertImageToHDF4`
2. Test opens Tools > Convert Image To > HDF4
3. Conversion appears to complete but file tree is empty

## Expected Behavior
- Image should be converted to HDF4 format
- Converted file should appear in the file tree
- Image metadata (rank, dimensions) should be accessible

## Workaround
Test is currently disabled with `@Disabled` annotation. The HDF5 image conversion test (`convertImageToHDF5`) works correctly.

## Notes
This appears to be a bug in the HDF4 image conversion functionality, not just the test.