Common Error Messages

If Resizer encounters errors as it processes files it will log these and the first 20 errors will be displayed at the end of the job.


It is in general the case that where there are more than 20 errors for a given job, that they are usually of the same type or of a small number of types that are likely to appear among the first 20 errors. To view the next 20 without fixing the problem for the first 20, you need to remove the first 20 problematic files from the Folder In temporarily. Since the files are processed alphabetically you can usually simply remove all files up to the required point in the alphabet.


If an extension of a filename is not among Resizer’s supported file formats, it will simply ignore these files and will not log these as errors.

The most common error types are listed below.

Memory Error

This will generally affect large files, depending on your computer’s capabitilies. The files need not be a large in size, they can simply have many pixels. The current version of Resizer is not suitable for very large images so other software must be used to bring these to within common sizes.


Memory Errors on a given image may affect subsequent images in the same job which would otherwise not run into memory problems. It is therefore advisable to run larger images separately to smaller ones. One rough but easily implemented solution is to use Windows Explorer to order your images by Size and then move all those above a certain size into a separate folder, so that you can run two jobs instead of one, thus reducing the number of Memory Errors. However, this will not always guarantee success as file size and pixel size are not always proportional and the size of the input file is not the only cause of Memory Errors.

Access is denied error when converting from pdf files

This error is a known issue which we intend to address soon. However, in most cases, the process succeeds despite the error, so check your output files.

Unsupported BMP compression

A number of bmp files are compressed using algorithms that Resizer does not understand. We are considering supporting these compression types in future, but for now these are unsupported.

Broken Data Stream when Reading Image File

This error is similar to the MemoryError above and affects larger files.

Known Issues

non-ASCII characters

GIF and PDF files as input seem to behave erratically when the filenames include non-ASCII characters. Until these issues are resolved, please rename these files using (ordinary English) ASCII characters.

Output issues

For the MTV, MNG, J2K, J2C formats, converting files into/from these formats may results in occasional very subtle thin horizontal lines.

For PNG to JPG/JPEG conversions the transparency found in files with an alpha channel such as RGBA (e.g. PNG) may turn into a colour other than white.

For conversions from PPM to FITS, PNG32 and PNG64 the output may include streaking lines and/or coloured spots.

For GIFS, rotation might change the background colour changed.

Resizing PDF files to very large sizes (e.g. 15000 x 20000 pixels) occasionally results in a blank pdf page.


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