File to String Pattern for uploading to a server

I need to upload some images to a server. This is done with a json object. The json object has 2 values, a timestamp and a Base64 encoded string of the image. I am using the jackson library and was wondering if this is a good way to upload the images. I am worried about memory consumption if I happen to upload images asyncronusly in the future. Here is is...

@JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
public class Photo {

    @JsonIgnore
    private String path;
    private String id;
    @JsonProperty("ts")
    private long timestamp;

    public Photo(long timestamp, String path) {
        this.timestamp = timestamp;
        this.path = path;
    }

    public String getData() {
        Bitmap bm = BitmapFactory.decodeFile(path);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bm.compress(Bitmap.CompressFormat.JPEG, 50, baos);
        bm.recycle();
        byte[] byteArray = baos.toByteArray();
        try {
            baos.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return Base64.encodeToString(byteArray, Base64.DEFAULT);
    }
}

I'm not familiar with Android at all, so just some generic Java notes:

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I'd rename bm to bitmap. A little bit longer variable names are usually easier to read and maintain.

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The constructor should validate its input parameters. Does it make sense to call it with null or empty string as path or a less than zero timestamp? If not, check it and throw a NullPointerException or an IllegalStateException. (Effective Java, Second Edition, Item 38: Check parameters for validity)

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It is a bad idea to use printStackTrace() in Android exceptions.

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I don't know if it differs from general Java or not but closing a ByteArrayOutputStream in Java has no effect. You might be able to omit it.

StackExchange Code Review Q#17680, answer score: 2